The Desiro Classic represents the original design of the Desiro series. It was introduced in 2000 with the DB Regio class 642, which is still the largest operator of the Desiro Classic today. The vehicles each consist of two car bodies, which rest in the middle on a common Jakobs bogie. Each car is powered by an underfloor diesel engine from MAN or MTU, which is available with an output of 275, 315, 335 or 360 kW. Power is transmitted via a hydromechanical five-speed gearbox. The vehicles are equipped with fully automatic Scharfenberg couplings and can be operated with each other in multiple. A planned multiple operation with vehicles of the other DB series 64x was not implemented due to a lack of suitable software.

The trains are often used on branch lines on which the use of locomotive-hauled trains no longer made economic sense and some of which were about to be closed down. On some routes, such as the Gräfenberg Railway from Nuremberg to Gräfenberg, now only vehicles from this class are used that can run an optimal timetable for their performance profile. Thanks to the automatic couplings, it is possible to split the trains at the designated points and thus implement winging without the need for additional personnel. Depending on the operator and the route, the vehicles are used with different interior fittings. There are vehicles that have a total of 12 seats in first class and 98 seats in second class, as well as vehicles without first class.

In Germany, DB Regio operates 234 Desiro Classic and four other operators a total of 53 more. Abroad, the largest contingent consists of 120 examples of the Romanian CFR class 96, followed by 60 Austrian ones, which are used as class 5022. A total of 167 other vehicles can be found within Europe in Denmark, Greece, Slovenia and Hungary. Overseas, the sole operator is the North County Transit District, which operates a network in northern San Diego County, California. Twelve Desiro Classics are used there as NCTD Sprinters, which have been maintained by a consortium of Veolia and Bombardier since 2009. The vehicles have more powerful air conditioning and made negative headlines in 2013 due to a temporary shutdown due to excessive wear on the brakes.