Modeling intra-individual fluctuations in estradiol and progesterone may provide unique insight into the effects of ovarian hormones on the etiology and treatment of nicotine dependence. This randomized placebo-controlled laboratory study tested the independent and interactive effects of intra-individual ovarian hormone variation and nicotine on suppression of tobacco withdrawal symptoms and smoking behavior. Female smokers randomized to 21 mg nicotine (TNP; n=37) or placebo (PBO; n=43) transdermal patch following overnight abstinence completed three sessions occurring during hormonally distinct menstrual cycle phases. At each session, participants provided saliva for hormone assays and completed repeated self-report measures (ie, tobacco withdrawal symptoms, smoking urge, and negative affect (NA)) followed by an analog smoking reinstatement task for which participants could earn money to delay smoking and subsequently purchase cigarettes to smoke. Higher (vs lower) progesterone levels were associated with greater reductions in NA. Higher (vs lower) progesterone levels and progesterone to estradiol ratios were associated with reducing smoking urges over time to a greater extent with TNP compared to PBO. There was an interaction between Patch and estradiol on NA. With TNP, higher-than-usual estradiol was associated with greater decreases in NA. However with PBO, lower-than-usual estradiol was associated with greater decreases in NA. These results suggest that the effects of TNP on mood- and smoking-related outcomes may vary depending on the ovarian hormone levels.