Abstract: A water soluble mixed fertilizer composition in solid form and a method of producing the fertilizer composition. The fertilizer comprises a mixture of urea, phosphoric acid and at least one potassium salt selected from the class comprising potassium sulphate, potassium nitrate and potassium chloride. Ammonium salts selected from the class comprising ammonium nitrate and ammonium sulphate may optionally also be added to the mixtures. Solid fertilizer compositions possible according to this invention include compositions which contain between 5 and 42% nitrogen, between 2 and 15% phosphorus and between 1 and 38% potassium, these values being elemental mass as a percentage relative to the total mass of the composition.