The aim of this study was to compare adverse mood effects of two different doses of medroxyprogesterone acetate (MPA) during postmenopausal hormone replacement therapy (HRT) in women with and without a history of premenstrual syndrome (PMS). The study was designed as a randomized double-blind cross-over study and included 36 postmenopausal women at three health care areas in northern Sweden. The women received 2 mg estradiol continuously during five 28-day cycles and 10 mg or 20 mg MPA sequentially for 12 days during each cycle. The main outcome measures were mood and physical symptoms noted on a daily rating scale. We found that physical symptoms did not differ between 10 and 20 mg MPA. Both women with a history of PMS and women without responded with more negative mood symptoms with the lower dose of MPA. In women with previous PMS the higher dose of MPA enhanced positive mood symptoms. With respect to mood and physical symptoms, the aim to lower MPA doses in HRT is unwarranted.