Abstract Electrical Submersible Pump (ESP) application is challenged by wells with 4-1/2", 5", 5-1/2" casings and 7" liner/casings with Y-tools. The standard approach was limited to use of conventional 3.75" ESP system with Induction motor, only suitable for 5-1/2" and 7" casings without Y-tool. The Ultra Slim 319 series (3.19" OD) ESP with use of Permanent Magnet Motor (РММ) illustrates the benefits of slim line ESP application under such challenging conditions. The paper discusses 3 successful cases for both Oil and Gas wells. The Ultra Slim 319 ESP with РММ was used: To increase the flow rate and provide higher reliability from а well that was recompleted with 5" liner. The production achieved was 4000 BPD For gas well unloading from а well completed with 4-1/2" liner or frac tubing Deployed inside а 7" #29 liner with Y-tool having bypass of 2-3/8". The bypass allows standard slick line/WL tools to access the reservoir. The use of Ultra Slim ESP enabled the operator for deeper installation for stable production. The use of РММ increased the reliability of the entire system by lowering the internal motor temperature rise and in addition lowering the current per barrel produced. The run life achieved is 1300 days in the case of the 5" liner application. The gas well unloading has been successful, however the Operator decided to shut down the project due to macro-economic reasons. The cases of 7" liner with Y-tool are currently under operation and stable. Ultra Slim ESP with Permanent Magnet Motor extends the ESP applications to completions that are out of reach for standard ESP with induction motors. The Ultra Slim ESP with РММ can provide: Higher production rates Wider ESP application range Longer run life where there is а risk of static pressure depletion Reduced per-barrel production cost due to the use of PPM, which decreases current amperage requirements and enhances efficiency СО2 footprint due to lower energy per barrel produced. This paper illustrates the versatility of Ultra Slim ESPs, which can address various challenging well scenarios and achieve target performance parameters. This information will be valuable for global ESP applications facing similar issues where solutions have not yet been identified.