This article updates the only previous systematic literature review of child outcomes of nonabusive and customary physical punishment by parents. The outcomes differ by methodologic, child, and subcultural factors as well as by how the physical punishment was used. All six studies that used clinical samples (including four randomized clinical studies) and all three sequential-analysis studies found beneficial outcomes, such as reduced noncompliance and fighting, primarily when nonabusive spanking was used to back up milder disciplinary tactics in 2- to 6-year olds. Five of eight longitudinal studies that controlled for initial child misbehavior found predominantly detrimental outcomes of spanking. However, those detrimental outcomes were primarily due to overly frequent use of physical punishment. Furthermore, apparently detrimental outcomes have been found for every alternative disciplinary tactic when investigated with similar analyses. Such detrimental associations of frequent use of any disciplinary tactic may be due to residual confounding from initial child misbehavior. Specific findings suggest discriminations between effective and counterproductive physical punishment with young children. More research is needed to clarify the role of spanking and alternative disciplinary tactics in control system aspects of parental discipline.