We propose a new technique called stable-PUF-marking as an alternative to error correction to get reproducible (i.e. stable) outputs from physical unclonable functions (PUF). The concept is based on the influence of the mismatch on the stability of the PUF-cells' output. To use this fact, cells providing a high mismatch between their crucial transistors are selected to substantially lower the error rate. To verify the concept, a statistical view to this approach is given. Furthermore, an SRAM-like PUF implementation is suggested that puts the approach into practice.