Objective: To measure test-retest reliability of the Stop-Signal Task (SST) and the Conners' Continuous Performance Test (CPT) in children with ADHD. Methods: 12 children with ADHD (age 11.46 plus or minus 1.66) participated in the study. Primary outcome measures were stop-signal reaction time (SSRT) for the SST and CPT's commission errors (%FP). For each participant, we acquired three morning (8:00am) measurements and behavioral observations, separated by two 7-day intervals. Reliability of cognitive measures and behavioral observations was measured using the Intraclass-correlation coefficient (ICC). Results: ICC values for SSRT and %FP were 0.72. Consistency of behavioral observations was much lower (ICC = 0.41). Conclusion: Both the SST and the CPT yielded reliable measurements in ADHD children. Our findings lend further support to using these measures in the study of ADHD. (Contains 4 tables.)