To understand the sequealae of action monitoring failures, most previous studies have focused on neural (e.g., the ERN and Pe) and behavioral (e.g., post-error slowing) measures associated with correct trials that precede and follow errors. However, trials that precede and follow errors are not always correct, and no study to date has examined RT and ERP indices in double-error sequences that could shed additional light on multiple response monitoring failures. In the present study, we examined ERP and behavioral data surrounding double-errors to explore the possibility that double-errors could either result from the failed detection of the first error, or from a reduction in compensatory post-error behavioral adjustments. Results indicate a normal ERN and Pe surrounding double-errors; however, errors that followed errors were characterized by reduced post-error reaction time slowing. These data are discussed in terms of existing response monitoring data, and in terms of the utility of double-errors to shed light on distinct types of response monitoring failures.