The operational functioning of the Medium Pressure Decomposer (MPD) at Pak Saudi Fertilizer was not good already along its complete history. Several modifications in the vessel were implemented, however high biuret, tube leakage, capacity limitation and solution carry over problems were still persisting. After acquisition of plant by Fauji Fertilizer Corporation a detail study on the MPD was carried out and the problem area was identified. On the basis this study short and long term solutions were proposed. Vessel was replaced in 2008 after operation of 5 years even at 125% plant load.