Premature birth is common worldwide and does not show signs of decreasing. In rich countries, assisted reproductive techniques contribute to maintain the rate high. Infants born prematurely are more at risk for a series of complications that could affect their cognitive and emotional performances well into teenage years and adulthood. Research on premature delivery is complicated by a series of methodological difficulties and is still largely based on data collected decades ago, when medical procedures in the neonatal units were different. Moreover, the development of socio-cognitive abilities in infants born preterm, in particular concerning moderate to late prematurity, is still understudied. The Special Delivery study was set up to address these gaps in the literature,through a short-term longitudinal study. A multi-method approach provided tools to explore different cognitive and social abilities from birth up to 24 months of age. Infants born at extremely low gestational ages and with complicated medical situations were excluded, in order to better explore the influence of prematurity alone. This thesis focuses on social attention and language between 13 and 24 months. Infants born preterm showed a delay in language abilities at 18 and 24 months and gestational age correlated positively with both receptive and expressive vocabulary size at both ages. Also some social attention behaviours were affected by prematurity. In particular, responding to joint attention and initiating behavioural request had lower scores in the preterm born sample, while initiating joint attention had no relation with the participants� birth status. With regard to the relation between social attention and language, the effect of gestational age on receptive vocabulary at 24 months was completely mediated by responding to joint attention skills at 13 months. It was concluded that prematurity in a healthy sample affects mainly responding to joint attention, which in return has a negative impact on subsequent language development.