Abstract: The objective of this study was to study the susceptibility of Naegleria fowleri trophozoites to Amphotericin B-combined chlorpromazine investigated the activities of single drugs used in combination with amphotericin B compared to those of each drug alone in vitro. The 50% inhibitory concentrations (IC50) and 100% minimal concentrations (MIC100) were calculated for single drugs and the drugs combination with fixed combination ratios of IC50 of amphotericin B. Single drugs, amphotericin B had the best IC50 and MIC100 scores against N. fowleri trophozoites. chlorpromaxine, Artesunate and azitromycin had following IC50 and MIC100 scores against trophozoites. However, we found that chlorpromazine in combination with amphotericin B was the best synergistic drug against N. fowleri trophozoites. According to single drugs, chlorpromaxine, artesunate and azitromycin plus amphotericin B had also been synergistic drugs against N. fowleri trophozoites. It was suggested that the combined use of these agents may be beneficial in treating Primary amoebic meningoencephalitis.