Purpose Minimally invasive procedures are increasingly important in pediatric urology. However, experience is still limited with minimally invasive operations on the upper urinary tract in infants. We analyzed 3 minimally invasive procedures (pyeloplasty, heminephroureterectomy and nephrectomy) in children younger than 1 year. Materials and Methods We analyzed 67 children (mean ± SD age 5.1 ± 2.9 months) undergoing minimally invasive pyeloplasty in 26 patients (group 1), heminephroureterectomy in 18 (group 2) or nephrectomy in 23 (group 3) with regard to technical aspects, surgical outcome and complications. Preoperative and postoperative ultrasound and mercaptoacetyltriglycine renal scan were statistically evaluated in groups 1 and 2. Results Mean ± SD patient weight was 6.4 ± 1.8 kg and mean ± SD operative time was 113.2 ± 41.6 minutes. Conversion to open surgery was necessary in 1 pyeloplasty. One complication (missed intraoperative bowel perforation) occurred. No blood transfusion was required in any child. After pyeloplasty there were improved tracer clearances (mercaptoacetyltriglycine scan) and improved morphologies of the pyelon (ultrasound) in all patients. In groups 1 and 2 there was no statistical difference between preoperative and postoperative partial function of the affected kidney. Mean ± SD followup was 32.5 ± 19.8 months. Conclusions Minimally invasive procedures on the upper urinary tract in children younger than 1 year are technically challenging, and require expertise of the surgeon and the entire team. Given these assumptions, such procedures can be safely performed with excellent functional outcomes.