Investigations on outdoor wintering of honeybee colonies were carried out in Mishan County, Heilongjiang Province, China, where the average temperature in the coldest month can be -19C, and the lowest -33C. in the first stage of the experiment (1980 - 82), survival of the colonies in the outdoor group traeted with \"chemical additives\" was 24% higher. In 1984 - 86, when hives outdoors were covered with a tarpaulin alone or with a straw mat, the average survival of additive-treated colonies was also higher than that of control colonies.