OBJECTIVE : The purpose of the study was twofold: (1) to assess the ability of hearing-impaired adults in the developing world to independently and accurately assemble a pair of hearing aids by following instructions that were written and illustrated according to best-practice health literacy principles; and (2) to determine which factors influence independent and accurate task completion. DESIGN : Correlational study. Study sample: Forty South African and 40 Chinese adults with a hearing loss and their partners. The participant group included 42 females and 38 males ranging in age from 32 to 92 years. RESULTS : Ninety-five percent of South African and 60% of Chinese participants completed the assembly task, either on their own or with assistance from their partners. Better health literacy, younger age, and a more prestigious occupation were significantly associated with independent task completion for the South African and Chinese participants. Task accuracy was significantly linked to higher levels of cognitive function among South African participants, while a paucity of valid data prevented an analysis of accuracy from being conducted with the Chinese data. CONCLUSION : Individuals of diverse backgrounds can manage the self-fitting hearing-aid assembly task as long as health literacy levels and cultural differences are considered.