OBJECTIVE To determine the clinico-demographic features and laboratory parameters of children with severe combined immunodeficiency (SCID). METHODS Case series. METHODS Department of Paediatrics and Child Health, the Aga Khan University, Karachi, from July 2006 to July 2011. METHODS Thirteen infants who were discharged with a diagnosis of SCID were inducted in the study. Their clinicodemographic features and laboratory parameters were determined. Descriptive statistics has been used for computing frequency and percentage. RESULTS The median age at diagnosis was five months; 5 infants presented within 3 months of life. Three-fourth (77%) were males. Most of the infants were severely malnourished (85%) at the time of presentation. More than two-thirds (69%) were products of consanguineous marriages. All subjects had severe lymphopenia {absolute lymphocyte count (ALC) ranging between 170 - 2280} and low T and B lymphocyte counts. CONCLUSIONS SCID should be considered in infants presenting with severe and recurrent infections. Low ALC (< 2500/mm³), is a reliable diagnostic feature of SCID. These infants should be promptly referred to a facility where stem cell transplant can be done.