The present study was conducted to determine the species composition of the family Coccinellidae (Coleoptera) in the tropical deciduous forest of Huautla, Morelos, Mexico in the south-central part of the Sierra de Huautla Biosphere Reserve (REBIOSH) during the period 2018–2019. Richness and abundance were quantified, and the expected richness was calculated with estimators. A total of 1,743 specimens belonging to two subfamilies, 12 tribes, 25 genera, and 52 species were recorded. The rainy season, particularly in August, was the most diverse, while the most abundant month was March (dry season). Several new state records for Morelos were found: Scymnobius flavifrons (Melsheimer), Scymnobius sordidus (Horn), Scymnus (Pullus) bryanti Gordon, Scymnus (Pullus) dozieri Gordon, Scymnus (Pullus) enochrus Gordon, Scymnus (Pullus) fraternus LeConte, Scymnus (Pullus) gilae Gordon, Brachiacantha indubitabilis Crotch, Brachiacantha quadrillum LeConte, Hyperaspis conspirans Casey, Hyperaspis globula Casey, Thalassa montezumae Mulsant, Diomus texanus Gordon, Paraneda viridescens Timberlake, Psyllobora renifer Casey. The following are reported additionally as new country records for Mexico: Scymnus (Pullus) mimoides Gordon, Calloeneis angelica Gordon and Hanley, Hyperaspis dobzhanskyi Gordon, Hyperaspis esclavium Dobzhansky, Hyperaspis oculifera Casey, Decadiomus austrinus (Gordon).