The article analyzes how themes are translated from English to Indonesian in the novel "Muhammad: his life based on the earliest sources". The researchers found that the most common type of theme is the topical theme, and there were shifts in thematic structure in all types of themes. In the topical theme, 5 themes were deleted and 15 were shifted to other grammatical functions. In the textual theme, 18 themes were deleted, 2 were shifted, and 4 were added. In the interpersonal theme, 3 themes were deleted and 1 was added. The translation process can affect thematic equivalence and pattern, so translators need to pay attention to thematic and grammatical structure to convey meaning accurately.