This study was carried out to determine how the water soluble, the available P₂O_5 and urea-N would change in the course of time, when the mixtures of calcium superphosphate and urea with lime for fertilizer which occurred in Korea and largely contained calcium .carbonate were made. Three kinds of materials, i. e., calcium superphosphate, urea and lime for fertilizer were used in this study. Three kinds of mixed fertilizer i. e., A. B and C were made up by mixing these materials to satisfy he following formula. 1. Ca(H₂PO₄)₂+ CaCO₃+CO(NH₂)₂→Ca₂H₂(PO₄)+ H₂CO₃+ NH₃ 2. Ca(H₂PO₄)₂+ CaCO₃+CO(NH₂)₂→Ca₃(PO₄)₂+ H₂CO₃+ NH₃ 3. Ca(H₂PO₄)₂+ CaCO₃+CO(NH₂)₂→Ca₃(PO₄)₂+ H₂CO₃+ CaCO₃+ NH₃ A,B and C were placed in desiccators respectively a six month period. During the time of storage, the water soluble, the available phosphoric acid and urea-N were measured once a month, seven times with the control measurement. The results may be summarized as follows. 1. None of A, B and C showed any change in the urea-N with the lapse of time. This fact indicated that the combination of calcium superphosphate and urea with lime for fertilizer was not unfavourable. 2. A, B and C decreased in the amount of water soluble P₂O_5 with the passage of time. This fact indicated that the mixing of calcium superphosphate and urea with lime for fertilizer was unfeasible. 3. The available P₂O_5 in any of A,B and C did not undergo a change as time went by. This fact suggested that the combination of calcium superphosphate and urea with lime for fertilizer was favourable.