The β decay endpoint energies corresponding to the decay from ¹⁵⁰Pm to levels in ¹⁵⁰Sm have been measured for the first time. The measurement has been made with a β – γ coincidence setup of two thin window Planar HPGe detectors and four Clover HPGe detectors. This measurement is a part of the program, taken up at VECC, on β – γ spectroscopy that would be utilized to characterise long lived β decaying isomers in nuclei.