OBJECTIVES Each state sets its own guidelines regarding eligibility and services for Medicaid. Therefore, people with similarly low socioeconomic status across the different states may not be of the same likelihood to enroll in Medicaid. State policies proposed to address uninsured population include the expansion of Medicaid programs. This study aimed to examine the demographic and geographical factors influencing the Medicaid enrollment for a representative sample of non-institutionalized population in the US. METHODS This study used the household survey data from the Medical Expenditure Panel Survey (MEPS) (2006, Panel 5&6) to explore the predictors for enrollment of Medicaid programs. The study population (n=2879) was defined as males, 19-64 years old, and with the income of, and lower than middle level (family income as a percentage of poverty). The cut-off of middle poverty level was used, according to some state eligibility criteria as high as 300% federal poverty line. Females were excluded in order to eliminate pregnancy-related Medicaid enrollment. Chi-square tests were performed on age, marital status, employment status, education level, and region compared to those who reported no insurance coverage over the year. A stepwise logistic model was also applied to identify predictors from the descriptive analyses. RESULTS Among the MEPS male respondents, 27% of people reported their enrollment in Medicaid in 2006. People with older age and being unemployment were more likely to be enrolled in Medicaid programs. Compared to people from South region, those from Northeast, Mid-west, and West regions were more likely to be Medicaid enrollees [Odds Ratios (Confidence Interval): 3.598(2.686, 4.822), 2.591(1.955, 3.434) and 2.941(2.349, 3.681), respectively]. CONCLUSIONS The states in regions other than the South were more likely to help poor people enrolled into Medicaid. This study suggested that a Medicaid expansion of Medicaid enroll in the South among the currently uninsured population is warranted.