The maximal rate of glucose influx in Hymenolepis diminuta decreased when CL- in the incubation medium was replaced with acetate, benzoate, bicarbonate, formate, hippurate, iodide, lactate, mandelate, or nitrate. The effect of Cl- deletion on glucose influx using any of these anions was reversed when worms were incubated in Krebs-Ringer saline for 15 min. Glucose in the incubation medium increased 36Cl- influx in worms, while in Na+-free media the presence of glucose had no effect on 36Cl- influx. Influx of 10 mM 36Cl- in H. diminuta was inhibited by unlabeled Cl- in the incubation medium. Hymenolepis diminuta accumulated glucose aginst an apparent concentration differnce when Cl- in the incubation media was replaced with acetate, bicarbonate, or nitrate. The influx of Cl- appears couples with the influxes of Na+ and glucose, but the data do not show whether the influxex of these molecules are mediated through a common "carrier."