This prospective study is to evaluate the feasibility, efficacy and safety of interventional cardiac catheterization in infants < 2500 gm compared to infants ≥ 2500 grams. This included infants through the first 60 days of life in New Children Hospital, Cairo University from January 2015 till January 2018. The study group (< 2500 grams) included 37 patients with mean age of 15.6 ±13.6 days and mean weight of 2.35 ±0.13 Kg, while the comparative group (≥ 2500 grams) included 164 patients with mean age of 26.2 ±18.4 day and mean weight of 3.54 ±0.71 Kg. Each adverse event (AE) was classified according to either a domain of attributability i.e. access or the seriousness i.e. major and minor. The procedures included balloon atrial septostomy (BAS), pulmonary balloon valvuloplasty (PBV), PDA stenting and radiofrequency (RF) perforation of pulmonary atresia. The success rate in the study group was 83.8 % while 93.9% in the comparative group, P = 0.04. The complications were higher in the study group (48.6% versus 20.1 %, P