In this investigation, CSC was prepared from 3 standard cigarettes (Kentucky reference (KR) 1R4F, 1R5F and a Virginia flue-cured Canadian industry monitor (CIM) (factor A). Two smoking conditions (factor B) were employed: "ISO" (puff volume, 35 mL; duration, 2 s; interval, 60 s.) and Canadian mandated "Intense" (55/2/30 with filters taped). CSC was trapped using either a Cambridge filter pad or an electrostatic precipitator (factor C). Each CSC was prepared 5 times and 3 replicate counts obtained per dose (8 levels ranging from 0 to 500 µg/plate) resulting in a 3x2x2 factorial experiment with 5X3 replicates for all doses > 0. The purpose of the experiment was to determine the significance of the 3 factors on revertant colony counts using TA98 and TA100 in the presence of S9. Factor significance was evaluated using an appropriate ANOVA. With respect to TA 98, smoking condition was found to have a highly significant effect (P value <0.0005) up to a dose of 250 µg/plate. Cigarette type was a highly significant factor at all dose levels. With respect to cigarette type, CIM was significantly different from KR1R4F and KR1R5F but the difference between KR1R4F and KR1R5F was not significant. Method of CSC collection was not a significant factor at any of the dose levels utilized in this experiment. With respect to TA100, smoking condition and cigarette type were significant factors but only for doses between 75 and 500 ug/plate and 100 to 500 µg/plate respectively. In contrast to the TA98 results, method of condensate collection was found to be significant when colony counts at doses of 250 and 500 µg/plate were examined. A quantitative investigation of factor effects was carried out based on the specific activity of the various CSC preparations as determined from a regression analysis of dose response curves.