Wiesbaden was a farming town until well into the 19th century: in 1804, 284 out of 400 households still had a small farm with livestock. There was no trade worth mentioning, few trades of a supra-regional character, the upper class of the bourgeoisie derived their wealth from the operation of inns and bathhouses, from the casino lease or from their work as senior civil servants. At the beginning of the 19th century, only three merchants and one grocer had assets of more than 8,000 fl. Moreover, these assets were largely invested in real estate and pension assets, i.e. there was hardly any active capital in the form of trading capital and stocks of goods. The founding of manufactories and factories remained the exception.

With the abolition of the guilds in Nassau in 1819 and the expansion of the infrastructure, trade and commerce gradually increased. A few factories were established, such as the cloth factory of the Löwenherz brothers in the Nero Valley (1842) and Franz Caspar Nathan's Lohmühle mill, also located in the Nero Valley. However, both companies met with resistance from the local population due to the pollution of the Nerobach and had to cease production. In 1836, Nassau joined the Customs Union, and in 1852 a uniform system of weights and measures was introduced in the duchy.

In 1843, the Nassau Trade Association was founded in Wiesbaden. In 1847, 14 of its 812 members described themselves as "manufacturers". The association's tasks included holding examinations for journeymen and advertising its own products; from October 1846, it regularly organized industrial exhibitions at which the products of the local trade were presented. The establishment of a chemical laboratory for training purposes by the chemist Carl Remigius Fresenius in Kapellenstraße in 1848 was groundbreaking.

In June 1860, the general freedom of trade was introduced in Nassau. Now many foreigners also settled in the town. In 1863, a chamber of commerce was founded for the Duchy of Nassau with its headquarters in Wiesbaden. Despite this, there were only 252 dependent male workers in Wiesbaden in 1861, spread across one wool, one cloth and two silk factories, seven weaving mills, two fulling mills, one iron foundry (with 16 workers), five lime kilns, 14 brickworks, two porcelain factories, four oil refineries, two mills, five beer breweries, 15 brandy breweries, one steel spring factory, two vinegar factories and twelve water mills. The gas lighting company had the highest number of employees with 38 workers. Only six steam engines with a total of 36 HP were used for production in the same year.

The establishment of insurance companies at the beginning of the 19th century continues to be of great importance for Wiesbaden's service sector. Pension and life insurance companies also chose Wiesbaden as the location for their headquarters; by 1866, there were already 16 of them. In the same year, eight banks were located here, and three of the bankers were among the city's highest taxed citizens. In 1840, the Landeskreditkasse was founded as the first state credit institution (since 1849 Nassauische Landesbank). In 1860, the cooperatively organized Vorschusskasse was established, and two years later the new "Verband der Wirtschaftsgenossenschaften am Mittelrhein" (Association of Economic Cooperatives on the Middle Rhine) took up residence in Wiesbaden. In 1865, the Wiesbadener Sparkassenverein was founded, which merged into the Vereinsbank in 1913.

Industrial settlements were established in Biebrich and Amöneburg. Also in Biebrich, Wilhelm Gail founded a factory for parquet flooring and woodworking with its own sawmill in 1858; it employed around 200 workers around 1910. Schierstein is the location of Glyco Metallgesellschaft(Federal-Mogul Wiesbaden), which was founded in 1897. In the last third of the 19th century, the area around Dotzheim railroad station established itself as a new industrial area. One of the most important companies in Dotzheim was Maschinenfabrik Wiesbaden GmbH, which emerged from the merger of the companies founded by Wilhelm Philippi and Carl Kalkbrenner around 1860. In 1910, it produced elevators, cranes, electric hoists, heating systems and iron constructions of all kinds.

The products of other Wiesbaden companies can be categorized as medical technology in the broadest sense. Even today, the Institut F. Ad. Müller Söhne, a studio for artificial eyes, is still flourishing today. The company Rossel, Schwarz and Co., which chose Dotzheim as its headquarters in 1897, manufactured orthopaedic devices. The Vaselinefabrik und Mineralöl-Raffinerie of Dr. Th. Steinkauler, which moved its headquarters from Frankfurt am Main to Biebrich in 1892, was a supplier to the pharmaceutical industry.

Two large breweries, the "Makkaroni- und Eierteigwaren-Fabrik Vater und Co. GmbH" founded in Biebrich in 1890, several bottling plants for mineral water and finally the expanding wine and sparkling wine industry are evidence of the upswing in the food and luxury goods industry. The foundation for Wiesbaden as a center of European sparkling wine production was laid by the wine merchant Johann Jacob Söhnlein, whose "Rheingau Sparkling Wine Factory" was established in Schierstein in 1864. Until the Second World War, Söhnlein was overtaken by Sektkellerei Henkell AG, which had moved its production facility from Mainz to Biebrich in 1909. In 1987, Söhnlein and Henkell merged and operated under the name "Henkell und Söhnlein Sektkellereien KG" until 2009.

In 1913, the number of out-of-town guests still amounted to around 200,000. However, the end of the First World War brought about the collapse of the spa industry in its old glamorous form. Many branches of industry also experienced a slump at the time. In contrast, Wiesbaden established itself as a publishing city and a location for the film industry after the Second World War. In addition to many traditional manufacturing companies, numerous high-tech companies settled in Wiesbaden in the post-war period. The German branch of the American Dow Corning Corporation, market leader in silicone technology, has been located in the Hessian state capital since 1983. Development and expansion projects to Eastern Europe are managed from here. Eckelmann AG has been producing systems for electronic machine control since 1977. Smiths Heimanns, now a British company, manufactures X-ray inspection systems for checkpoints at airports. Concrete finishing and corrosion protection are the trademarks of Sinnotec GmbH. The research-based biopharmaceutical company AbbVie was founded in 2013 as a spin-off from the healthcare group Abbott.

In the service sector, auditing, management and tax consulting firms in particular characterize the modern face of Wiesbaden, which has once again become a media location thanks to branches of the telecommunications, industrial and consumer electronics sectors. As a result, the structure of the old spa town has undergone lasting change in recent decades.