The present invention relates to compositions comprising cupredoxins, and their use to inhibit angiogenesis in mammalian cells, tissues, and animals, and particularly the angiogenesis that accompanies tumor development and particularly in humans. Specifically, the present invention relates to compositions comprising the cupredoxin(s), and or peptides that are variants, derivatives or structural equivalents of cupredoxins, which retain the ability to inhibit angiogenesis in mammalian cells, tissues or animals. These compositions may be peptides or pharmaceutical compositions, among others. The compositions of the invention may be used to treat any pathological condition that has as a symptom or cause, inappropriate angiogenesis, and particularly inappropriate angiogenesis related to tumor development.