A multi-stage gearbox of planetary construction, in particular a power split transmission of a work engine, having a housing which accommodates four planetary sets, several shafts and several shift elements including at least a brake and a number of clutches. Selective engagement of the shift elements implements different gear ratios between a drive shaft and an output shaft. The drive shaft is connected to a carrier of the second planetary set while the sun gear of the second planetary set is coupled with a third shaft and the ring gear of the second planetary set is coupled with a fourth shaft. The output shaft is connected to a carrier of the fourth planetary set, and a fifth shaft is firmly connectable to the housing by a first brake.