ABSTRACT.Naegleria fowleriamebae, but not those ofN. australiensis, N. gruberi, orN. lovaniensis, demonstrated enhanced motility when placed in proximity to mammalian cells. Amebae of nonpathogenic species ofNaegleria, however, were more motile in cell culture medium than the amebae ofN. fowleri.The locomotory response of highly pathogenic mouse‐passagedN. fowleriamebae to nerve cells was greater than axenically cultured amebae. The enhanced mobility elicited by whole nerve cells or disrupted nerve cells was not directed migration but chemokinetic.Naegleria fowleriresponded to disrupted neuroblastoma cells more vigorously than to disrupted African green monkey kidney (Vero) cell