The present invention relates to a process for making a fertilizer in granular form, said process comprising: (i) Providing a mixture comprising (a) potassium sulfate (A) and (b) one or more binders, said one or more binders including water, wherein at least 30 wt.%, preferably at least 40 wt.% of said potassium sulfate (A) has a particle size between 75 and 1000 µm; (ii) Subjecting the mixture to a granulation step to form granules, preferably wherein said granulation step is effected in a wet tumbling granulator; and (iii) Drying the granules; and (iv) Optionally, sieving of the granules thus obtained to retain granules that have a particle size between 1 and 6 mm, preferably between 2 and 5 mm.