Thirty  colonies (1^st Carniolan hybrid) were chosen to study the effect of Formic acid 60% and Oxalic acid 3% on productivity of infested colonies with Varroa mite. The brood rearing ratios in treated honeybee colonies were significantly surpassed those of untreated colonies during 2003 and 2004 years. The highest rates of increase in sealed brood cells due to formic-oxalic acids applications. In 2003, the rates of increase in number of wax combs covered from both sides with adult bees after Formic-oxalic acids applications ranged between 8.39% on December 7 and 45.52% on March 18. The corresponding values in 2004 were 2.64% on September 14 and 32.40% on June 22. Treating the honeybee colonies with Formic-oxalic acids increased the amounts of stored honey as compared with those in untreated colonies. The rate of increase in 2003 ranged between 2.48% on January 18 and 53.3% on March 6. The corresponding range in 2004 was 1.5% on November 25 and 35.7% on September 26 and October 8. The rates of increase in the amounts of stored honey were high in treated colonies during citrus, clover and cotton flowering periods. The amounts of stored pollen grains in honeybee colonies were higher in colonies treated with Formic-oxalic acids than in untreated colonies. In 2003, the rate of increase ranged between 5.61% on May 29 and 52.82% on March 6. The corresponding values in 2004 were 3.28% on January 30 and 76.18% on September 26. As in case of stored honey, the rates of increase in the amounts of stored pollen were high during the citrus, clover and cotton flowering periods. Generally, treating the honeybee colonies with formic and oxalic acid caused on obvious decrease of infestation with Varroa mite to the minimum rate and productivity increase of honeybee colonies moreover cheap costs, available of easy use and more safe.