Caecilia marcusi is a species of caecilian in the family Caeciliidae. It is found in the southwestern Amazon Basin in Bolivia and Brazil; its range is likely to extend into Peru. Caecilia marcusi is similar to Caecilia mertensi and could be its synonym.

Caecilia marcusi is a subterranean species inhabiting lowland tropical rainforest at elevations below 400 m (1,300 ft). It is locally threatened by habitat loss.

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