AbstractPast vegetation and climate changes reconstructed from a sediment core from Laguna Atezca, Molango, Mexico, provide new insights into the environmental and cultural histories of the Sierra Madre Oriental during the last 1700 yr. Pollen, microscopic charcoal, sediment chemistry, loss on ignition, and magnetic susceptibility indicate that three phases of human occupation, deforestation, and erosion (ca. A.D. 280–890, ca. A.D. 1030–1420, and ca. A.D. 1680–present) alternate with two phases of abandonment (ca. A.D. 890–1030 and ca. A.D. 1420–1680). Forest composition of the two abandonment phases differed, with cloud forest taxa (Liquidambar, Ostrya/Carpinus, Ulmus, etc.) dominating the pollen record during the first phase, andQuercusandPinuspollen characterizing phase two. These differences may reflect a climate change in which the second phase was drier than the first; Alternatively, the increase inPinusandQuercusmay have been caused by a human-induced decline in soil fertility. The Laguna Atezca record also differs from several other Mesoamerican paleoenvironmental records in that it shows no evidence of drought at the end of the Classic Period, ca. A.D. 900.