Although many studies have shown that cognitive effect expectancies are associated with drug use and drug treatment outcomes, few studies have compared effect expectancies with drug response following drug challenge. Healthy male and female volunteers (n=19, ages 21-35) who reported using cocaine 1-4 times per month completed the Cocaine Effect Expectancy Questionnaire (CEEQ: [Schafer, J. and Brown, S.A. (1991). Marijuana and cocaine effect expectancies and drug use patterns. Journal of Consulting and Clinical Psychology, 59, 558-565.]), were challenged with cocaine (0.9 mg/kg, i.n.), then completed a series of visual analog scales (VAS) and the Addiction Research Center Inventory (ARCI) at 15 min intervals for 3 h following cocaine administration. Significant positive correlations were found between global negative expectancies and peak responses on the VAS measures "Good," "Happy," "High," "Stimulated," and "Desire to Use Cocaine," and on the LSD subscale of the ARCI post-cocaine administration, and between global positive expectancies and the MBG subscale of the ARCI, and on VAS items "Anxious" and "Good" post-cocaine administration. Global positive expectancies also were positively correlated with peak systolic blood pressure, and global negative expectancies with peak heart rate after cocaine administration. These results suggest that negative and positive effect expectancies both play a complex role in the subjective experience of cocaine effects, and thus likely in the progression of non-use to recreational use, in the transition to abuse, and in individualized treatment strategies.