Previous studies have examined the reliability of scores derived from various Stroop tasks. However, few studies have compared reliability of more recently developed Stroop variants such as emotional Stroop tasks to standard versions of the Stroop. The current study developed four different single-stimulus Stroop tasks and compared test-retest reliabilities. The four Stroop tasks included two standard Stroop tasks (color-word and picture-word) as well as two emotional Stroop tasks (color-word and picture-word). The four Stroop tasks were administered on two occasions, separated by 1 week, to 28 undergraduate students. Test-retest reliability coefficients were high for standard and emotional Stroop tasks when reliability was measured using response latencies alone. However, test-retest coefficients were unacceptably low when reliability estimates were calculated using difference scores. The findings have important implications for clinical and experimental use of standard and emotional Stroop tasks.