GAMBUSIA AFFINIS, brought from America to Europe, is now widely used as an ecological agent for combating Anopheles larvae. Gambusia has become acclimatized in all the South European countries, Germany and Austria included, as well as in China, Japan and Siam. The first successful introduction of Gambusia from America to Europe took place in 1921 into Spain whence it was spread to different parts of Italy and thence all over South Europe. Gambusia was brought in 1924 from Italy to the U.S.S.R. and became widespread all over the country: Transcaucasus, Daghestan, North Caucasus, Azof and Black Sea region, the South Ukraine, the Moscow district, Turkestan, etc. Experiments on acclimatization of Gambusia in Turkestan made a good start at the end of 1929. In the summer of 1935 we made an attempt to acclimatize them on the rice fields of Turkestan. In the present paper we record only a few matters dealing with nutrition. The analysis of Gambusia food was done by the usual method in ichthyology of examining the stomach contents. Gambusia were collected from the rice fields in the morning (at 6-7 a.m.), afternoon (at 1 p.m.) and evening (at 8 p.m.) over a total period of 10-15 days between 9 June and 1 September. A total of 500 stomachs was collected. Out of this number 273 were analysed, 54 being from young fish. The analysis showed that Gambusia mostly feeds on products of animal origin. Only in 30 of the 219 adult stomachs analysed were remnants of vegetable food found-13-7 % of the total. In young fish the percentage was 12-9 vegetable. The food included the following animals: Mollusca, Crustacea (Copepoda, Cladocera), Acarina, Insects (Rhynchota or Hemiptera, Coleoptera larvae, Ephemeridae larvae, Trichoptera larvae, Chironomidae larvae, Culcidae larvae, Anopheles larvae), Rotatoria. And the following plants: Chlorophaeaceae, Desmidaceae. All these were present in the adults (male and female) and young examined, except that Mollusca did not occur in the females and young, and Trichoptera not in the females. These exceptions may have been accidental. We did not find any stomachs with exclusively vegetable food remains.