The analysis of nuclear-encoded mitochondrial genes (N-mt genes) in Drosophila has shown that most of the duplicated N-mt genes acquired testis-biased expression. These genes tend to be old and have energy-related functions. They are often relocated and many originate through retroposition, a duplication mechanism that appears to facilitate the acquisition of testis expression. These specific patterns reveal strong selection for retention of these duplicates in flies. Since selection could be different for mitochondrial functions in male germline because males do not pass the mitochondria to the offspring and are under strong male-male competition to fertilize the females, we predict that the same selective pressures could operate in other species lineages. To test this, we analyzed the entire set of genes annotated as N-mt genes in the human genome. We found 290 N-mt genes (i.e., 18%) that can be grouped into gene families which are the product of 164 gene duplication events. While around 32% of the new genes showed tissue-specific expression and testis had the highest number of tissue-specific duplicates, the percentage of this kind of duplicates was small (6%) compared to Drosophila (54%). Unlike Drosophila duplicates, human testis-specific duplicated genes are young and have diverse functions. These differences might reflect differences in the selective pressures for mitochondrial function during spermatogenesis and fertilization between Drosophila and humans, differences in the response to these pressures or differences in the efficiency of selection between these species.