Percolation segregation in binary size mixtures of potash and urea were quantified at three strains of 2, 6, and 10% and two strain rates of 0.25 Hz and 0.5 Hz. To prepare binary size mixtures, three coarse mean sizes: 3,675, 3,075, and 2,580 mu m of potash and urea were mixed with three fines mean sizes, 2,180, 1,850, and 1,550 mu m, of potash, and two fines sizes, 2,180 and 1,850 mu m, of urea, respectively. Based on experimental results, the percentage of segregated fines and the normalized segregation rate (NSR) of fines for binary mixtures increased when strain rate was increased from 0.25 to 0.5 Hz. NSR and percentage of segregated fines also increased with increase in strain from 2 to 10%. In addition, NSR increased when strain was increased from 2 > 6 > 10% for size ratios 1.7:1.0, 2.0:1.0, and 2.4:1.0 (p < 0.05). At the three strains, 2, 6, and 10%, NSR for potash was higher (0.06, 1.13, 1.40 kg/kg-h) versus urea (0.17, 0.62, and 0.69 kg/kg-h) except at strain of 2%, for the same size ratio 2.0:1.0 when coarse size was 3,675 mu m (p < 0.05).