The present study investigated (a) the effects of group therapy ix on values and behavioral adjustment of hospitalized psychiatric patients, and (b) differential effects of directive versus non-directive group therapy in effecting desired therapy outcomes. Thirty subjects selected from among patients at Wyoming State Hospital were matched on age and sex and then randomly assigned to two experimental groups and one control group. Experimental group I received directive group therapy, experimental group II received non-directive group therapy and the control group participated in recreational activities. Both experimental groups and the control group participated in 12 weekly sessions, which were structured according to the respective objectives, mode of leadership style and/or activity intended for each group. All subjects were administered the Rokeach Value Survey prior to, and following the 12 group sessions. Each subject was also rated on the MACC Behavioral Adjustment Scale by two independent raters (hospital ward attendants) both before and after the experimental period. Porter's (1950, pp. 180-182) "counseling categories" were used to measure directiveness and non-directiveness of the group therapy leaders. Pretest comparisons among the experimental and control groups showed the groups to be essentially comparable (not significantly different) either in median rankings of values on the Rokeach Value Survey or in ward attendant ratings of the subjects on the MACC Behavioral Adjustment Scale. Posttest comparisons on the same variables (i.e., value rankings and ratings of behavior) indicated significant differences among the experimental and control groups on two of the 18 instrumental values of the Rokeach Value Survey, but no differences on any of Rokeach's 18 terminal values. Posttest changes over pretest value rankings occurred as much in the control group as in the experimental groups and the direction of changes varied with each group. Thus, no definitive benefits of one type of group procedure over another occurred. Further, the limited number of values for which posttest differences were observed between the experimental and control groups were well within the amount of normal change that could be expected from chance probabilities alone. It was therefore concluded that these particular changes in value rankings were essentially negligible and thus not attributable to either of the treatment modalities. Possible effects of group therapy in general, as well as any differential effects of directive versus non-directive group therapy were also studied in terms of behavioral ratings of subjects by hospital ward attendants. Statistically significant results on this variable clearly supported the value of both therapy groups over the control group for effecting positive changes in post-treatment behavioral ratings of the study's hospitalized subjects. However, the results did not demonstrate sufficient differences between the two experimental groups to conclude superiority of one leadership style over the other. A descriptive analysis of individual movement (direction and amount of change) from pretest to posttest ratings of behavioral adjustment was presented, and posttest differences between subjects subgrouped according to psychiatric diagnosis and number of psychiatric hospitalizations were discussed in terms of clinical rather than statistical inferences. The results of the study were discussed in reference to previous research related to human values, and Rokeach's viewpoint with regard to personal values and value changes was considered in light of the findings of the present study. Some possible implications of the study results were suggested, with particular reference to some of the unique characteristics of the study sample, including differing psychiatric diagnoses and chronicity of subgroups of the subjects, and a possible lack of motivation on the part of some subjects for participation in therapy groups. Several delimitations of the study were discussed, and recommendations for further research of this nature were offered.