AIM: This study assesses the results of treatment using the mini-percutaneous nephrolithotipsy (PCNL) procedure on renal stone patients in a lateral position under ultrasound guidance, performed at the Ha Noi Hospital of Post and Telecommunications. METHODS: The study was conducted with 650 kidney stone patients who were treated using the ultrasound-guided mini-PCNL procedure in a lateral position, at the Ha Noi Hospital of Post and Telecommunications, over the period from June 2018 to June 2019. RESULTS: For the 650 patients, the mean age was 47.3 ± 7.6 (from 21 to 91 years old); the mean size of stones: 19.4 ± 1.2 mm (from 12 mm to 60 mm); the mean operative time: 49.3 minutes (from 37 to 90 min); the mean period of hospitalization: 3.9 days (from 3 to 12 days); the mean stone-free rate (SFR): 90.6%; the rate of second surgery: 1.07%; hemorrhage complication: 0.8%; urinary tract infections: 7.7%; septicemia: 0.6%; administered open surgery: 0.46%; and administered other methods: 0.76%. CONCLUSION: Renal stone fragmentation using the mini-PCNL procedure, performed on patients placed in lateral position under ultrasound guidance, is a method that is effective, beneficial, and safe for patients with renal stones and upper ureteral stones.