The objectives of this research were 1) to study profitability and liquidity of SME rice mill businesses in Thailand, 2) to study the relationship between characteristics of rice mill businesses and profitability and liquidity, and 3) to compare profitability and liquidity among small and medium sized rice mill businesses. A total of 80 samples in this study were 36 companies and 44 partnerships. The data was collected from the annual financial statements during 2005 to 2009. This study classified the rice mill businesses into medium and small groups based on their fixed assets. Descriptive and trend statistical analysis methods were used in this research. Two hypotheses were tested by carrying out correlation coefficients, and two were tested by carrying out t-test. This research was to set statistical significance at .01 and .05 levels. The results indicated that from 2005 to 2009, 1) most rice mill businesses had non-smoothers in profitability ratios and higher than 0 (zero). It also indicated that most rice mill businesses had net income from operating activities but non-smoothers in profitability. In addition, most rice mill businesses had an increase in current ratio and liquidity ratios higher than 1, which indicated that most rice mill businesses had current assets higher than current liabilities. 2) The results from characteristics of SME rice mill businesses show positive, whereas the size-return on common equity relationship shows negative. The financial structure-return on common equity relationship is positive and the age- return on noncurrent assets relationship in partnerships shows a negative age-quick ratio relationship in companies. 3) Furthermore, the result showed that profitability ratios were not significantly different in accordance with the size of a company, but return on common equity were significantly different based on the size of partnerships. In addition, current ratios were not significantly different in accordance with the size of a company, and neither were partnerships.