The few extant reports examining the relationship between diurnal patterns of pre-cessation smoking and cessation nicotine replacement use suggest that this relationship may be important in preventing smoking relapse. The current study evaluated three interventions to increase nicotine gum use: standard treatment (ST, N = 31), ST plus brief feedback about nicotine attitudes and knowledge (BF, N = 32), or BF plus contingent monetary reinforcement for nicotine gum use (CM, N = 34). Subsets of the 97 randomized subjects were selected based on availability of adequate data for analyses: baseline phase (i.e., 6-7 days of ad libitum smoking, N = 63) or the treatment phase (i.e., 13-15 days of treatment, N = 47). For both cigarettes and nicotine gum, participants showed a characteristic pattern of increasing use during the morning hours, followed by stable use in the afternoon and evening, with a steep decrease prior to sleep onset. Patterns of diurnal gum use did not differ by compliance intervention. Greater morning use of cigarettes or gum was associated with smoking relapse while greater evening and night use of cigarettes or gum was associated with abstinence. Understanding of diurnal patterns of smoking and NRT use may ultimately inform tailored scheduling of NRT.