Introduction This review summarizes the current literature for the prevalence and medical costs of noncommunicable chronic diseases among adult Medicaid beneficiaries to inform future program design. Methods The databases MEDLINE and CINAHL were searched in August 2016 using keywords, including Medicaid, health status, and healthcare cost, to identify original studies that were published during 2000− 2016, examined Medicaid as an independent population group, examined prevalence or medical costs of chronic conditions, and included adults within the age group 18− 64 years. The review and data extraction was conducted in Fall 2016− Spring 2017. Disease-related costs (costs specifically to treat the disease) and total costs (all-cause medical costs for a patient with the disease) are presented separately. Results Among the 29 studies selected, prevalence estimates for enrollees aged 18− 64 years were 8.8%− 11.8% for heart disease, 17.2%− 27.4% for hypertension, 16.8%− 23.2% for hyperlipidemia, 7.5%− 12.7% for diabetes, 9.5% for cancer, 7.8%− 19.3% for asthma, 5.0%− 22.3% for depression, and 55.7%− 62.1% for one or more chronic conditions. Estimated annual per patient disease-related costs (2015 US dollars) were $3,219− $4,674 for diabetes, $3,968− $6,491 for chronic obstructive pulmonary disease, and $989− $3,069 for asthma. Estimated hypertension-related costs were $687, but total costs per hypertensive beneficiary ranged much higher. Estimated total annual healthcare costs were $29,271− $51,937 per beneficiary with heart failure and $11,446− $20,585 per beneficiary with schizophrenia. Costs among beneficiaries with cancer were $29,384− $46,194 for the 6 months following diagnosis. Conclusions These findings could help inform the evaluation of interventions to prevent and manage noncommunicable chronic diseases and their potential to control costs among the vulnerable Medicaid population.