The present communication deals with two new species of the genus Ptychobothrium Loennberg, 1889 collected from Mystacoleucus marginatus at Maesa Stream, Chiang Mai in the month of January, 1998 i. e. P. mystacoleucysi n. sp. and P. rojanapaibuli n. sp. P. mystacoleucysi n. sp. differs from all the know species of the genus with the characters, scolex triangular, testes (25-30) in number, pre-ovarian, cirrus pouch placed in the center, vagina long tube, ovary bilobed with 10-12 acini, uterus reticulate, filled with many eggs, uterine pore rounded. placed near to the anterior margin of the segment and granular vitellaria where as P. rojanapaibuli n. sp. having heart shaped scolex, bothridia compressed, immature segments square, testes 65-70 in number, in two fields, big and rounded, post-ovarian, cirrus pouch near to the anterior margin of the segment, big, cirrus curve, uterine pore not touching to the anterior margin of the segment, ovary 'u' shaped, uterus reticulate, and vitellaria granular in 3-4 strips.