Distribution of values of GC-content of the fragments in spatial structure of chloroplast, mitochondrial, and bacterial genomes were explored. It was found that GC-content in the fragments for most genomes is identically but not independent distributed varaible. Two main types of distribution have been revealed: the gradient distribution and centrally symmetrical distribution. Chloroplast genomes have only a gradient distribution. In bacteria, for the GC-poor genomes, a centrally symmetrical distribution is observed, while there is a gradient distribution in the GC-rich genomes. In mitochondria, both types of distribution are present, the type of distribution depends on the type of an organism.