Sex differences exist in brain function and behavior. Recent studies in rodents have started to reveal molecular mechanisms underlying sex differences in memory formation. It is becoming clear that sex differences are not only reflection of sex hormones, but also reflect differences in synaptic signaling mechanisms including the role of synaptic kinases. My main focus on this talk will be that there are male-specific gene transcriptional regulations underpinning spatial and contextual fear memory, two types of hippocampus-dependent memories. These transcriptions are CREB-dependent and they involve regulation via the Ca2+/calmodulin kinase cascade.