Emotional memories are a central part of human experience and the inability to forget them in few cases makes their study relevant and evidence for their potential modulation important to address. This thesis comprises four studies on the modulation of emotional memories with behavioural and pharmacological manipulations at memory formation, retrieval and reconsolidation, testing mnemonic performance with several methods and neural correlates with functional MRI. In summary, the studies of this thesis highlight the impact of emotional arousal and cortisol on the formation of emotional memories, the necessity of cortisol for the recruitment of the emotional memory brain network upon retrieval and the update of the neural memory representations for emotional events, and the interaction of cortisol with sleep for the reconsolidation of emotional memories. Overall, this thesis shows that emotional memories can be altered at all memory stages, with potential clinical implications for psychotherapy and the treatment of psychological disorders.