Birch and pine wood unbeaten kraft pulp-bacterial cellulose composites were prepd. on culturing of Acetobacter xylinum in the fibers of the pulps. The C sources were simple saccharides (glucose, galactose, mannose, xylose, and arabinose). The breaking length and the tear index of the birch composite (glucose as C source) were resp. twice and thrice as high, and those of the pine composite were resp. by 80 and 70% higher than those of the unbeaten pulps. With xylose, the composites were even slightly better. The apparent d. of the composites was higher by a few per cent.