The paper starts by questioning the theory of second demographic transition (SDT) and its universal relevance in the field of marriage behavior and family organization in low fertility context, arguing for more differentiated approaches. With an aim to illustrate the contextual specifics of post-socialist countries in general and of Serbia in particular, the author claims that analyzed changes have not just been delayed or incomplete in comparison to more developed European countries, but shaped by specific modernization processes, which led to rationally developed strategies in overcoming structural risks, although, without ideational changes typical to the theory of SDT. Slow changes in marital behavior and family organization in Serbia are illustrated in recent sociological (empirical) research findings. The perceived changes are linked to specific structural risks (war, slow transformation and enduring economic hardships, weak state and low trust in institutions, etc) and value characteristics (persistence of materialism and traditionalism, but with increasing ambivalence). The connection between structural and ideational changes is considered through social stratification variable by relying on Coale's model on necessary preconditions for behavioral changes as well as on social deprivation concept. Having in mind upper social strata (more educated and better off), the value changes precede the behavioral that are adapted to economic uncertainty, which still force more traditional marital and family patterns. Therefore, there is a rank of different options, from extended family (for a short period at the beginning of marriage or after divorce) to separated leaving (of married partners) in parental households (due to refusing the extended family option thus creating quite specific "living apart together" form), combined with dominant strategy of prolonging the marriage. Hence, for upper social strata, marriage is still a universal but negotiable institution since more alternative options (although attractive and in accordance to changing values) are deemed irrational (have no obvious benefit). As regards the lower social strata (less educated and worse off), marriage is more in accordance with their higher inclination to traditional values, but general value liberalization legitimizes possible failures (divorces, extra marital births), which, even if not desired or economically rational, happen due to lower capacity to command life. For that reason, cohabitations and extra marital births are more common among actors at the lower end of the stratification ladder. The paper concludes that adaptive strategies related to traditional patterns of family organization dominate in Serbia, which might be illustrated by the fact that every third of one parent families lives in extended families. Even with significant structural changes (and economic improvements) in Serbia in the near future it is realistic to expect familism as an influential context, which suggests the spreading of cohabitation primarily as a pre- marital option (but more desired than forced).