This experiment was conducted to examine feed intake, digestibility and volatile fatty acid (V FA) composition of ruminal juice of NaOH treated rice straw or NaOH treated rice straw pellet through digestibility experiment and the determination of ruminal pH and volatile fatty acid pattern for lamb. Tweleve male lambs weighing 45 ㎏ on average body weight were divided into 4 treatments i.e. control group (raw rice straw chopped in 5 ㎝), 1% NaOH treated group, 3.5% NaOH treated pellet A group (1.7-1.8 ㎝ in diameter and 4.5㎝ in length) and 3.5% NaOH treated pellet B group (2.4 ㎝-2.5 ㎝ in diameter and 3-4 ㎝ in length). Among 12 lambs, 8 lambs were used for digestion trial and 4 fistulated lambs were used for measuring the VFA pattern and changes in pH of rumen juice. The results obtained were summarized as follows. 1. The daily rice straw feed intake of lambs fed rice straw pellet B (806 g/day) and rice straw pellet A (767 g/day) was higher than that of NaOH treated rice straw (679 g/day) or control group (396 g/day). 2. Digestibilities of dry matter, C. Protein, C. fiber and NFE in rice straw pellet B were the highest and that of untreated straw was lowest. Digestibilities of crude fiber and NFE in rice straw pellet A were higher than those of NaOH treated rice straw. However, the opposite trend were shown in those of dry matter, crude fat and crude protein. The contents of DCP and TDN of rice straw pellet B (1.42%, 51.39%) were highest and those of untreated straw (0.39%, 41.58%) were the lowest. 3. The total VFA production of rumen juice was the highest in NaOH treated rice straw pellet A group (101.93 m M/l) and was the lowest in control group (88.39 m M/l). In change of VFA. production, NaOH treated rice straw pellet A and B groups showed the peak at one hour after feeding and was half hour in NaOH treated rice straw. But control group was decreased for one hour. No significant difference was found in pH change of rumen juice collected. According to the present results, NaOH treated with or without palleting the rice straw is considered to be an improved source roughage for the ruminant animals.