Abstract: The article presents the results of an empirical study of the relationship between six types of interpersonal contradictions (contradictions of interests, activity-organizational and activity-authorizing contradictions, contradictions of opinions, personality-behavioral and value-normative contradictions) with two indicators perceived by members and experts of production-economic and three indicators of social-psychological effectiveness of a small group and informal subgroups in the group. 334 employees were surveyed in 42 production groups with a different profile of activity. It is established that between many types of contradictions and indicators of the effectiveness of the group and the subgroup, there are connections that are of an opposite nature. To isolate a group of informal subgroups, a special formalized algorithm was used. To study the types of interpersonal contradictions and types of efficiency, the author's toolkit as part of the computer technology "Group profile - Universal", GP-U (M-16) was used. The production and economic efficiency of the group according to the assessments of its members is determined practically by all types of interpersonal contradictions, whereas according to experts' estimates it is related (with one indicator only) to only one type of contradiction. The productive and economic efficiency of informal subgroups is determined, depending on the indicator under consideration, by all or most types of contradictions. Virtually all indicators of the group's social and psychological effectiveness depend on all types of interpersonal contradictions, and the identified correlations are stronger than the correlations between the contradictions and the production and economic efficiency of the group. At the level of informal subgroups, a similar pattern is revealed, but the correlations between the contradictions and this type of effectiveness are characterized by less force than at the group level. Some types of contradictions make a contribution to the socio-psychological effectiveness of subgroups, not only individually, but also in interaction with each other.