We document the composition by sex and size of 105 long-beaked common dolphins (57 males and 48 females) from a die-off in January–February 1995 in the upper Gulf of California, Mexico. Total length of males ranged from 191.2–264.7 cm and those of females ranged from 170.0–252.4 cm. These are the largest Delphinus reported to date anywhere in the world.