This experiment was conducted to determine apparent ileal and fecal digestibilities of protein sources for young pigs (15.6 kg BW) which were fitted with simple ileal T-cannulas. Experimental diets included one of the followings as a sole protein source: spray-dried plasma protein (SDPP), spray-dried blood meal (SDBM), soybean meal (SBM), isolated soy protein (ISP), dried skim milk (DSM), and fish meal (FM). The digestibilities of dry matter (DM), gross energy (GE) and crude protein (CP) in DSM-based diet were the highest (p < 0.05), and those of SDBM and SBM diets were the lowest at the terminal ileum. The average ileal digestibilities of essential amino acids (AAs) were 88.3, 84.7, 84.6, 83.4, 83.0 and 77.7% for pigs fed the DSM, ISP, SDBM, SBM, SDPP and FM diets, respectively. There were no significant differences in overall apparent ileal AAs digestibilities in DSM and ISP diets. Digestibilities of essential AAs in DSM, however, were significantly higher than those of ISP (p < 0.05). Among the essential AAs, the digestibility of arginine was higher except for SDBM or DSM, than other AAs. The ileal digestibilities of lysine, methionine and threonine were higher (p < 0.05) in pigs fed SDBM or DSM diet than in those fed SBM diet. Digestibilities for SDPP or ISP diet in these AAs were similar except for threonine which was higher (p < 0.05) for SDPP diet. The apparent ileal digestibilities of lysine and methionine ranged from 79.6 (FM) to 92.5 (DSM) and 75.4 (SDPP) to 88.7 (DSM), respectively. The apparent fecal digestibilities of average essential AAs were 90.4, 89.1, 86.0, 84.4, 84.2 and 80.8% in pigs fed the DSM, ISP, SDBM, SDPP, SBM and FM diets, respectively. The fecal digestibilities of essential AAs were higher (p < 0.05) in pigs fed the DSM and ISP. Lysine digestibility in pigs fed the DSM or ISP diet was higher (p < 0.05) than that of pigs fed SBM diet. Apparent essential AAs digestibility was the highest (p < 0.05) in pigs fed DSM diet, and was the lowest (p < 0.05) in pigs fed FM diet. Digestiibilities of essential AAs and nonessential AAs were higher when measured over the total digestive tract than at the end of the small intestine except for several AAs in SDPP, SDBM and SBM diets. In conclusion, whether it is fecal or ileal, the digestibilities of proximate nutrients and AAs in pigs fed DSM and ISP diet were the highest, and those of pigs fed FM was the lowest.