Last name Kostoff (Kostoff 
) , around the globe, is a rare family name. The family name Kostoff is habitual in Uruguay, where it is a rare surname, Bulgaria, and Argentina. Measured by absolute frequency, it most frequently occurs in the United States, Argentina, and Canada.
| VARIANT | COUNTRY |
|---|---|
| Kostoff | Canada, Argentina, France, United States, Bulgaria |
| jeff kostoff American swimmer; Olympic athlete, Pan American Games gold medalist, US (b. 1965) |
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| chris kostoff college basketball player (1994–1994) San Diego |
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