It has descriptively been analyzed a meaningful sample gotten from the Spanish version (translated and adapted by Royuela, 1994; 1996; 1997) of the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Derived from this analysis, it has statistically been proven the thesis that states that the indigenous populations tend to have good sleep quality due to the fact that the presence of urban pollution factors (electricity, technology, work pressure, among other aspects), which presumably affect it, is low within the indigenous surroundings. It is also considered that the sleep of the indigenous populations is generally conditioned by natural variations related to their genre, their life stages or some external factors that characterized their occupational performance or their geo-climate habitat.