Despite continued interest in ameliorating the posthospital psychological effects of hospitalization on children, there have been no analytic reviews of the research on this topic. The present study synthesized all known research that evaluated experimental interventions through the use of the Posthospital Behavior Questionnaire (PHBQ), by far the most commonly used method of examining posthospital behavior. The mean weighted effect size (ES) was +.44, Confidence Interval (CI).95 = +/- .10. Thus, on the average, children who received experimental interventions tended to change their behavior in the direction of psychological upset less than children who did not (z = +4.81; p < .00006). Analyses of ES moderators indicated significant variations (p < .05) associated with (1) the year of the report, (2) questionnaire format, (3) study design, (4) variations in experimental treatment, (5) subject's age, and (6) length of hospitalization. Psychoeducational preparation was not effective with younger children. The benefits of experimental interventions persisted up to 4 weeks after discharge.