Since possible predictor variables of marital adjustment are too numerous for a complete analysis in any one study, determination of the relative importance of such predictors is needed for theory development. In order to examine the importance of socioeconomic rewards, family development characteristics, and religiosity as predictors of marital adjustment, volunteer marital dyads (N=208) from a cross section of Protestant churches completed measures of marital adjustment, family development issues, religiosity and demographic questionnaires. Multivariate analyses of the three variables showed that religiosity was the strongest and most consistent predictor of marital adjustment, predicting twice as much variance as did socioeconomic rewards or family development characteristics. For both husbands and wives number of children was negatively related to marital adjustment. The data suggest that religion facilitates the adaptation process necessary to marital adjustment, perhaps by providing a set of norms by which to live. (WAS)