General Motors Corp. lost $763 million in 1980, marking the second losing year in its history.

The giant automaker's loss came on worldwide sales of $57.7 billion. The only other time GM ever lost money since its founding in 1908 and incorporation in 1916 was in 1921.

GM's loss for 1980 compares with its 1979 profit of $2.9 billion on sales of $66.3 billion.

For the last three months of 1980, GM's profits were $62 million on sales of $16.2 billion compared with a $426 million profit in 1979 on almost identical worldwide sales of $16.1 billion.

Issuing the company's year-end results for the first time since they assumed the top posts at GM were Chairman Roger Smith and President F. James McDonald. Referring to the last three-month period, they said in a joint statement: "The return to marginal profitability reflects the increased consumer demand for General Motors products. We believe we have turned the corner. While the recovery will not be rapid, we are confident the turnaround will continue into 1981."

They blamed the 1980 results on high interest rates, inflation, "economic sluggishness" in many countries and the continuing consumer shift toward smaller cars which enabled Japanese competitors to increase their share of the U.S. market.

Before tax considerations, and the profits from unconciliated subsidiaries, such as the General Motors Acceptance Corp. financial arm, GM's 1980 loss was an even more dramatic $1.4 billion worldwide.

The organization will have a tax credit of $385 million for 1980 compared with $2.2 billion paid in federal taxes for 1979 and the company record of $3.1 billion paid in 1978 when it racked up record profits of $3.5 billion sales of $63.2 billion.

GM said its directors yesterday declared a 60-cent dividend on common shares, payable March 10 to stockholders whose names appear on the company's books Feb. 11. It was the fourth straight quarter for a payout of that amount and compared with a dividend of $1.15 in the first quarter of 1980.

GM's U.S. employment in 1980 averaged 517,000 compared with 618,000 the year before. Worldwide the 1980 employment was 746,000 compared with 839,000 in 1979.

Smith and McDonald noted the cut in GM's worldwide employment in 1980 and that contributions to the employe stock purchase plan were suspended and no GM employe got any bonuses.

The GM loss was not unexpected. The trade newspaper Automotive News had predicted it at $1 billion.