In early 1959, the Bundeswehr tested Erma's MP58 prototype and rejected it with recommendations for improvements. Erma developed their new model, the MP59, in response to the Bundeswehr's demands. It was submitted for testing but by the time trials were arranged, the General Staff of the Bundeswehr had changed and new specifications were set out. The MP59 did not meet these new specifications and was therefore rejected. This led to the development of the MP60.
The MP59 was largely an improvement of the MP58, but utilized a new hydraulic buffer spring to regulate the fire rate. Upon testing, however, it was discovered that the spring wore out upon prolonged use and the fire rate gradually increased over time. The MP40 magazines used by the MP58 were ditched in favor of new "staggered" double-column magazine that fed bullets from each column in an alternating order. The MP59 utilized a sliding stock rather than a folding one and featured perforated barrel housing. Otherwise, like the MP58, it was constructed cheaply from sheet metal.