This mixed methods (qualitative and quantitative) study aimed to 1) illustrate the situations of intermediate care for older adults according to the Ministry of Public Health’s policy, 2) evaluate the implementation of intermediate care to older adults according to the Ministry of Public Health’s policy and 3) propose policy recommendations to improve intermediate care in Thailand. Seventeen healthcare facilities providing intermediate care to older adults were multi-stage sampled from the Ministry of Public Health provider sampling frame of 897 hospitals covering 4 regions from the North, Northeast, Central and the South. Key informants comprised 30 executives at the central and provinces, 1,008 intermediate care providers, and 23 academic experts attending final policy meeting. Questionnaires and guidelines for interview including group discussion were the tools used for data collection during September 2019 and June 2020. Quantitative data were analyzed with descriptive (frequency, percentage, mean, standard deviation) and inferential statistics (median test, paired t - test, t - test, Pearson correlation, and stepwise multiple regression). Qualitative data were analyzed by content analysis. The followings are main findings. 1. The hospitals in 8 provinces can be divided based on service data into 3 groups: 1) intensive intermediate care services, 2) moderate intermediate care services, and 3) moderate intermediate care services with limited evidence from questionnaire and individual inpatient data. Group 1 hospitals had longer length of stay (LOS) than other groups in all 3 conditions; stroke 9.2 days, traumatic brain injury 13.6 days and spinal cord injury 26.8 days. The stroke patients in group 1 hospitals showed better patient functional improvement by higher difference of Barthel index (DBI) than in group 2 hospitals (4.0 vs 1.8, independent t-test 3,381 = 12.51, p<0.01). The medical expense had a low positive correlation with LOS (r = .17, p< .01). The DBI has a positive correlation with LOS (r = .17, p<.05) but a negative correlation with age (r = -.04, p<.05). 2. Responses from 1,008 questionnaires gave a fair mean score for intermediate care service to older adults (x ̅ =3.6, S.D.=.5). The highest score was for policy acceptability (x ̅ = 4.0, S.D .= .6), followed by the feasibility of policy (x ̅ = 3.7, S.D. = .6), and lowest for cost support (x ̅ = 3.2, S.D. = .7). By Pearson’s correlation, the policy appropriateness had the highest correlation with the adoption (r=.73, p<.01), followed by the policy acceptability and the adoption (r=.67, p<.01). The sustainability of intermediate care was positively correlated with all dimensions of policy process and years of experience in intermediate care, with highest correlation with policy penetration (r = .57, p<.01). By multiple regression analysis, policy penetration (B = .411, t = 12.603, p<.01), policy feasibility (B = .161, t = 4.833, p<.01), and policy acceptability (B = .134, t = 4.425, p<.01) were predictors of sustainability (Adj. R2 = .367, p<.01). 3. Key success factors of the implementation of intermediate care policy from qualitative methods were listed: 1) executives with visions plan, set clear goal and constantly monitor results, 2) service provider commitment with good multidisciplinary teamwork, and 3) the service system preparedness, efficient resource sharing, shared practice guideline and care models with strong multidisciplinary network. Constraints were lack of staff’s understanding on policy and practice; inadequacy workforce and competent staff; shortage of resources or material including budget, and medical supply; and inefficient patient referral and information system. 4. Policy recommendations include clear policy communications cascading with localization flexibility, integrated seamless care by enhancing the role of family medicine, health workforce recruitment that fits with intermediate care demands, common information platform facilitating referral of data among providers and payers, extension of service scope to more health conditions and age groups, and establishment of appropriate and comprehensive payment systems.