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Visitation rates and mean numbers of visits per flower per day are determined at three altitudinal levels (2 200–3 600 m) in the high Andes of central Chile from quantified observations of flowers visitors to a total of 134 species of plants, studied over three flowering seasons. Significant altitudinal decreases in the mean no. visits/flower/minute and per day were recorded, with Level III flowers, on the average, being pollinated only about 1/2 as frequently and to as low as 1/4 as frequently in certain months, as Level I flowers. Visitation rates are generally highest in early and mid-summer at all altitudes. — The lower visitation rates at the higher elevations are due to lower insect abundance relative to plant resources and lower levels of activity for the insects present, stemming from the generally lower ambient temperatures. Seasonal differences in visitation rates may also be related to differences in insect …