In custodial interrogations, suspects tend to give disproportionate weight to immediate outcomes relative to future outcomes when deciding whether to confess or deny guilt. The current research examined whether the perceived (un)certainty of an immediate outcome influences suspects' short-sighted confession decisions.We hypothesized that suspects are more likely to make short-sighted confession decisions when an immediate punishment is certain versus uncertain and that the effects of a certain immediate punishment become stronger the longer suspects are interrogated.Using the repetitive question paradigm, college student participants (N = 164, 57% women, 87% Caucasian, M age 18.9 years) admitted or denied 20 illegal and unethical behaviors in an interview. Participants' admissions and denials received either an immediate punishment (answering repetitive questions) or a future punishment (meeting with a police officer in several weeks to discuss their misconduct). In addition, we manipulated participants' perceptions of the immediate punishment to be either certain or uncertain.Participants showed greater short-sightedness in their admission decisions when they perceived the immediate punishment to be certain versus uncertain. Moreover, the influence of the certain immediate punishment on participants' admission decisions tended to increase over time.These findings provide empirical evidence that the certainty of immediate outcomes may contribute to suspects' shorted-sighted confession decisions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).