The purpose of this study was to examine and compare the effects of hypohydration on heart rate (HR), systolic blood pressure (SBP), rate-pressure product (RPP), and rating of perceived exertion (RPE, 6-20 scale) in healthy male cigarette smokers (S) and male nonsmokers (NS) during long duration, submaximal exercise.  Eight untrained male S (M±SD:  age 25.8±5.3; VO_2PEAK 34.9±7.6) and eleven untrained male NS (M±SD:  age 25.6±3.4; VO_2PEAK 31.8±5.4) participated in the study.  Subjects performed 60 minutes of cycle exercise at 50% VO_2PEAK under a euhydrated treatment and hypohydrated treatment.  Hypohydration induced by controlled sauna exposure the night prior to testing yielded percent body weight reductions for S and NS of 2.2±0.6 and 2.4±0.5 respectively.  HR, SBP, RPP, and RPE measurements were recorded at rest, 5, 15, 30, 45, and 60 minutes of exercise.  Response variables “Δ” (hypohydrated minus euhydrated) were compared using repeated measures ANCOVA for group (S and NS) and time (rest, 5, 15, 30, 45, and 60 minutes).  Additionally, steady state measurements for HR, SBP, RPP, and RPE were determined by averaging values recorded at 30, 45, and 60 minutes of exercise.  Steady state response variables “Δ” (hypohydrated minus euhydrated) were compared between groups using 2-sample t-tests.  Paired t-tests were used to make within group comparisons.  Repeated measures ANCOVA yielded no significant interactions or main effects.  Two-sample and paired t-tests comparing steady state measurements indicated no significant differences.  Both groups showed slight increases in steady state HR, RPP, and RPE during the hypohydrated trial.  Steady state SBP was virtually unchanged in the NS between treatments, but the S demonstrated a slight decrease in steady state SBP during the hypohydrated trial.  The results from this study suggest that healthy male cigarette smokers and male nonsmokers have similar cardiovascular and subjective responses to submaximal exercise performed in a mild hypohydrated state.