The prefrontal cortex (PFC) plays an important role in cognitive processes such as working memory, but it is also involved in emotional and motivational processes such as anxiety and social interaction. Previous studies have shown that PFC neurons are modulated by different variables in one specific task, but it remains unclear how the same neurons respond during different tasks. Here we address this question by imaging the same PFC neurons in mice while they perform multiple tasks. We expressed the calcium indicator GCaMP6f in the medial PFC (mPFC) of C57BL/6N mice and implanted a GRIN lens to image mPFC neuronal activity during five distinct behavioral tests: A T-maze spatial working memory task, elevated plus-maze exploration, novel object recognition including free open field exploration, social interaction and discriminative auditory fear conditioning. We used generalized linear models to identify which task variables the neurons encoded. While many task variables were encoded by mPFC neurons, with many neurons encoding more than one variable, animals' position influenced cell activity most prominently across the different tasks. Neurons that encoded one variable in one session of a task tended to also encode this variable in other sessions of the same task. Similarly, neurons that encoded general task variables like the position or movement speed did so across different tasks. We also found that anxiety-like features were encoded by the same neurons across different exploration tasks. Overall, these findings indicate stability in the representations of task-relevant variables by mPFC neurons, both within and across tasks.