This investigation was conducted on cantaloupe plants (Cucumis melo var. Cantaloupensis, L.). Melon hybrid F₁ (Ananas) was grown on clay loam soil at Barramoon Experimental Farm (El-Dakahlia Governorate) during the two successive seasons of 1998 and 1999, to study the influence of soil dressing with mineral-P fertilizer at 0, 30, 60 and 90 kg P₂O₅/fed. either alone or in combination with P-biofertilizer (Phosphorien) at 3 kg/fed. on  plant growth, total yield and its components as well as fruit traits and chemical constituents in plant leaves. The interaction between main factors was also studied. In general, the obtained results can be summarized as follows:-      All studied characteristics of plants received mineral-P were generally better than those of unfertilized ones. Beside this, increasing the applied mineral-P rate from 30 to 90 kg P₂O₅/fed. significantly increased most parameters of  plant growth, total fruit yield and its components as well as all traits of fruit and concentrations of N, P, K and Ca in leaves.      Application of P-biofertilizer (Phosphorien) exerts significant increases in most studied characteristics of plant growth, yield and its components. In addition, it markedly improved fruit traits and muchly increased P and K concentrations in leaves as compared with those of untreated plants.      The positive interactions between mineral-P and Phosphorien inoculum have often been observed. The obtained values by using Phosphorien with mineral-P levels were generally increased than those of either alone. The greatest values were achieved by using 60 kg P₂O₅/fed. in the presence of Phosphorien. These values were nearly identical for those obtained by 90 kg P₂O₅/fed alone. From the foregoing results, it is evident that inoculation of cantaloupe seeds pre-planting with P-biofertilizer (Phosphorien) at 3 kg/fed. reduced the need for mineral-P manuring by up to 33.5%. In addition, the high costs of production and environment pollution problem could be reduced.