Objectives: Reports suggest women with bipolar disorder (BD) have high rates of perimenstrual mood worsening. In this prospective study, the authors compared healthy controls and depressed and euthymic BD patients on medications on mood levels, psychosocial function, and physical symptoms in the late luteal versus the early follicular phase. Methods: At baseline, the lifetime diagnosis of bipolar I disorder or bipolar 11 disorder, current mood episode, and absence of premenstrual dysphoric disorder in controls were confirmed with the Structured Clinical Interview for DSM-IV Disorders. Subjects were assessed across three menstrual cycles during the late luteal and early follicular phases. Clinicians administered the Structured Interview Guide for the Hamilton Depression Rating Scale and the Mania Rating Scale to assess levels of depression and hypomania/mania, respectively. Subjects completed self-report ratings on psychosocial function and perceived stress and tracked daily mood and physical symptoms on the National Institute of Mental Health Life Chart and the Daily Rating Form. Ovulation was verified objectively with mid-cycle luteinizing hormone urine dipsticks and serum progesterone levels. Results: The sample characteristics were similar among the three patient groups of healthy controls (n = 10), BD-euthymic (n = 6), and BD-depressed (n = 5). The two-way analysis of variance indicated a significant difference among the diagnostic groups on depression scores, psychosocial functioning, and levels of perceived stress. There was no significant difference for menstrual phase or the interaction of menstrual phase by diagnostic group. Conclusions: Mood symptom level, psychosocial functioning, perceived stress, and physical discomfort were unrelated to menstrual phase in patients with BD. Appropriate maintenance treatment may prevent menstrual related mood symptoms. Use of an objective marker of ovulation is critical for research involving menstrual related outcomes.