The components of a research program focussing on early mother-twin interaction is described. Preliminary data obtained from a questionnaire at two months post term, cross-sectional observations at the age of one year, a follow-up study involving home observation and parental interviews from birth to the age of 3, point to the specificity of this triadic situation. During the first months of life, the burden of material tasks and the increase in baby care leave little time for starting a relationship based on pleasure or play. The impossibility of responding simultaneously to the needs of two babies and the difficuty of forming relationships on an individual basis foster early concerns for egalitarianism. The degree of physical resemblance between the babies creates the problem of differentiating them. To tell twins apart, mothers rapidly tend to rely on behavioral characteristics to which they attribute a genetic basis. In contrast, differences in development between the babies that introduce the eventuality of the dominance of one of the twins are often denied. In this highly specific situation, mothers arrive at personal solutions of adjustment over the first 3 years, manifest in a certain number of psychological and educational attitudes. Analysis of these maternal attitudes may help to shed light on some of the features of later psychoemotional development in twins.