Behavioral performance in older adults is often characterized by normal error rates but longer response latencies compared to younger adults. The slowing of reaction times might reflect a compensatory strategy to avoid errors and might be associated with performance monitoring alterations. The present study investigated whether the ability to compensate for potential deficits influences age-related differences in performance monitoring. A modified flanker task was used with either accuracy or speed instruction. Both groups showed reliable differences between conditions: accuracy, reaction times and error-related negativities were reduced in the speed compared with the accuracy condition. Older adults showed smaller error-related negativities compared with younger adults and the reduction was more pronounced in the speed condition. Further, similar-sized error-related and correct-related negativities were found in older adults. Results indicate that performance monitoring deficits in older adults are related to deficits in behavioral performance, at least if they are forced to respond quickly.