Species richness in relation to crop plants is analyzed within the families of higher plants. Three groups have been made: (1) more than 10.000 species (5 families), (2) 1.000 to 10.000 species (50 families), (3) less than 1.000 species (20 families). Thus about 224.000 species from the estimated 250.000 species of higher plants have been included in this study. According to Hanelt and IPK (2001), altogether 7,000 species of crop plants exist. There is a positive correlation (r = + 0.56) between the number of crop plants and species diversity of the families. Important crop species within the selected families are indicated.