Currently, no culturally and linguistically adapted autism screening tools are available in South Africa. The aim was to determine the reliability and concurrent validity of the adapted English and Northern Sotho-translated Modified Checklist for Autism in Toddlers--Revised with Follow-up (M-CHAT-R/F). Reliability was confirmed with near-perfect agreement (p < 0.001) between the checklists in a sample of 158 Northern Sotho/English bilingual mothers of children with a low risk for autism. Concurrent validity between the Northern Sotho M-CHAT-R/F and the communication and socialization sub-domains of the Vineland Adaptive Behaviour Scales--3rd Edition was established with significant association at the 5% level. A third (33.5%) of the children showed a developmental delay. The checklists are valid and reliable, and may improve early identification that will render better long-term outcomes for children with autism in South Africa. Autism screening should be combined with developmental assessment. The study contributes to an emerging body of research on the development of contextually appropriate screening measures.