Rodríguez-Arévalo, I.*, R. Lira & I. Calzada (Unidad de Biotecnología y Prototipos, Universidad Nacional Autónoma de México, Campus Iztacala, Avenida de los Barrios s.n. Los Reyes lztacala, Tlalnepantla, Estado de México, C.P. 54090, México; *iselara@hotmail.com). A new species of Sicyos L. (Cucurbitaceae) from Oaxaca, Mexico. Brittonia 57: 43–46. 2005.—Sicyos mcvaughii, a new species from Oaxaca, is described and illustrated. It is similar to Sicyos sertuliferus Cogn., and grows in secondary tropical deciduous forest, between 20 and 630 meters.