An investigation of chiasms distribution in chromosomes 1, 2 and 9 in the human male has shown that each arm consistently has a characteristic and highly non-random distribution of recombination. The chiasma frequencies of chromosome regions corresponding to the major mitotic bands have been used to construct genetic maps under the assumption that there is no chromatid interference or chiasma movement and no difference between meiotic and mitotic band positions. This paper presents genetic lengths and recombination fractions for these bands and for combinations of bands in chromosomes 2 and 9. Our results are particularly useful for relating genetic distance to recombination fraction and for dealing with long stretches of chromosome which cannot easily be analysed by any other techniques.