Infection of human erythrocytes with the malaria parasite Plasmodium falciparum induces activation of organic osmolyte and anion channels in the host cell membrane. These channels supply the intraerythrocytic parasite with nutrients, dispose of metabolic waste products, adjust the host electrolyte concentrations to the parasite's needs, and lower the colloid osmotic pressure, thus preventing premature hemolysis of the osmotically challenged host cell. Four different types of anion channels (CFTR, ClC-2 or PSAC, an 18 pS inward rectifier, and an 80 pS outward rectifier) have been identified in human erythrocytes. Here, we show that the 80 pS channels underlie a serum albumin-dependent anion current. Both, the parasite in vitro development and the organic osmolyte permeability of the parasitized erythrocyte, reportedly depend on serum albumin, highlighting the pivotal functional significance of the 80 pS channel for the intraerythrocytic parasite development. (c) 2008 Elsevier Inc. All rights reserved.