The main objective of this research was to create a better understanding of the long term cognitive, behavioural and psychosocial consequences for children with Russell Silver Syndrome (RSS), a syndrome characterised by being born Small for Gestational Age (SGA) and having short stature and phenotypical facial features. A systematic review revealed a trend for SGA children is increasing cognitive difficulties with increasing age, possibly due to spatial difficulties. A comparison of the cognitive abilities of an RSS group and an age matched control group revealed a cognitive disadvantage in RSS children, particularly spatial difficulties. RSS children were also found to have more behavioural problems than control children, particularly symptoms of ADHD. An investigation revealed an increased incidence of Autistic Spectrum Disorder (ASD) in RSS than would be expected in the general population, though those with ASD symptoms were not found to form a distinct group of children with RSS. An investigation self esteem in RSS revealed that although they were physically smaller and perceived this, this was not impacting on their overall self esteem. In turn it was revealed that others were not viewing the physical symptoms of RSS as guiding their expectations. Overall the findings from this research were positive and have real life application. It was important that weaknesses, such as was found for spatial ability and hyperactivity and inattention are recognised. What this research was not able to conclude conclusively was why these patterns of behaviour were observed and this offers future directions for the research.