Questions of past human-environment interactions are best addressed by a research agenda that recovers complementary archaeological and paleoenvironmental data. We have used such an approach in our investigations at Laguna Tamarindito, a small lake located in the SW part of the Petén rainforest of Guatemala. In 1991, a sediment core was taken from the lake as part of a larger program of research examining the history of human-environment interactions in the Petexbatun region. We employ a conjunctive analytic approach to interpret the core, including archaeological survey of the lake's watershed, physical and chemical analysis of sediments, palynology, and molluscan ecology. Our analysis of this core reveals substantial paleoecological information about the past 10,000 years in this region. Study of the lake sediments, pollen, and gastropod populations indicates variation in regional climate, including two periods of significant drying. Changes in the rate of sedimentation in the lake can be related to the occupation of the region by Maya peoples beginning sometime between 2,000 and 1,000 years B.C. Sedimentation during the Late Classic ( A.C. 600--800) was slowed by a system of soil erosion controls. Palynological analysis indicate that Holocene period changes in the region's vegetation were roughly similar to the paleoecological record from other parts of the Petén, but with some significant differences. A pattern of human disturbance that differs somewhat from other parts of the Petén is also indicated by the pollen record. Most significantly, many major high forest species virtually disappear from the record during both the Late Preclassic and Late Classic periods, but are present during the intervening Early Classic.