A sports card sorter box/tray combination unit and card sorting method. The card sorter box/tray unit includes two mating half-sections which each include five card sorting bins. The sorting bins in the first half-section are numbered in sequence from 0 to 4 and the sorting bins of the second half-section are numbered in sequence from 5 to 9. With the tray-box unit in open and card sorting position the half-sections of the unit are aligned in substantially end-to-end orientation with the bins aligned in numbered sequence from 0 to 9. The card sorting bins of each half-section of the tray-box unit are open on their upper and inner sides so that sports cards can be easily slipped into the numbered bins. The half-sections of the tray-box unit each bear an upper cover and handle portion which cooperate together, when the unit is closed for card carrying and storage purposes, to close the upper sides of the sorting bins and maintain the enclosed sports cards in stored position therein. Utilizing the sports card sorting tray and card carrying and storage box unit in its card sorting operative position, a method of card sorting is practiced which yields the collection of sports cards in numbered sequence.