Memory, mood, and hormone levels were measured in 25 women during the menstrual and luteal phases of their cycles. Significantly lower visual memory (delayed recall) scores were found during the menstrual phase compared to the luteal phase. No phase differences were found on mood measures or on other memory measures including digit span, paired-associate learning, immediate recall of visual material, and immediate or delayed paragraph recall. The visual memory decrease was most prominent in approximately one-half of the sample and was significantly correlated with plasma progesterone in the luteal phase. For all subjects, paragraph recall scores were negatively correlated with free testosterone levels, whereas paired-associate learning was positively correlated with estradiol levels in the luteal phase. These results suggest that changes in memory test performance may be associated with sex steroid levels, particularly in some subgroups of women.