Objective:To determine if cultured feline Kupffer cells (KC) are as permissive for feline immunodeficiency virus (FIV) as cultured human liver macrophages are for HIV. Two types of infection likely to be relevant to thein vivosituation were used. KC were infected with either free virus or autologous infected peripheral blood mononuclear cells (PBMC).Methods:Feline KC were isolated by centrifugal elutriation from collagenase‐perfused liver; cultured cells were characterized by their morphological appearance and their erythrophagocytotic properties. After infection, viral replication was measured by enzyme‐linked immunosorbent assay, reverse transcriptase activity, immunofluorescence assay,in situhybridization and electron microscopic observations.Results:Three days after isolation, 85% of cultured KC were able to internalize red blood cells; 45% were CD4‐positive and 65% expressed a 24kD protein thought to be a receptor for FIV (CD9). After the addition of autologous infected PBMC or cell‐free supernatant of chronically infected IRC4 cells to KC cultures, a peak of viral replication was detected at day 28. Antigen revealed by immunofluorescence assay was present in only 0.4%, and viral RNA was detected byin situhybridization in 2% of the infected cells.Conclusions:FIV can replicate in cultured feline KC without inducing any cytopathic effect, which suggests that these cells may play a role in the physiopathology of FIV infection.AIDS 1995,9:447‐453