: We present the implementation of on-line Hebbian learning for NESPINN, the Neurocomputer for the simulation of spiking neurons. In order to support various forms of Hebbian learning we developed a programmable weight unit for the NESPINN-system. On-line weight modifications are performed event-controlled in parallel to the computation of basic neuron functions. According to our VHDL-simulations, the system will offer a performance of up to 50 MCUPS.