Background:   Diabetes mellitus and hypertension are major health problem in Thailand. Patients who suffer from these diseases experience undesirable symptoms and complications at target organs that affect levels of quality of life of patients. 
Purpose:   This study purposed: 1) to examine quality of life levels of diabetes patients and hypertensive patients with/without complications 2) to explore the method to increase levels of quality of life in diabetes patients and hypertensive patients with/without complications. 
Method:   Mixed method design was used in this study for examining quality of life of the patient. Sample of quantitative study include 543 patients with diabetes and/or hypertension and these patient were with/without complications. Study sample was recruited from 17 health care settings in Saraburi province. For qualitative study, sample was 36 patients with diabetes and/or hypertension, including with/without complications. Quantitative data was collected using WHOQOL-BREF-THAI. This questionnaire was tested for validity and reliability. The reliability was 0.82. With respect to qualitative study, data was collected by in-depth interview procedure using the list of 12 questions. Field note and voice-recording were performed during interview with the patient. 
Data analysis:  Demographic data was analyzed using frequency, percentage and S.D. Predictive factors of quality of life was analyzed by performing multiple regression procedure. Qualitative data was analyzed and categorized for major theme of perception of quality of life, levels of quality of life, and method to increase quality of life in diabetes mellitus and hypertensive patients.            
Results:   Average age of patient was 60.08 years (S.D.= 13.37)  The majority of study sample was female (65.54%, n= 350). The major group of patient was married (66.88%, n= 374 ), and education levels was primary school  (71.64%,  n= 389). The majority of patient was low income, 0-1,000 Baht a month (36.1%, n= 196). Many patients can control diabetes mellitus and hypertension (60.22%, n= 327). The period of diabetes was 3.64 years (S.D.= 7.06), hypertension was  5.47 years (S.D.= 6.89), and both diabetes and hypertension was 2.25 years (S.D.= 8.12) Average score of quality of life of the patient was moderate levels ( = 3.42, S.D.= 1.79). With respect to perspective of the psychological aspect was the lowest score ( = 2.97, S.D.= 1.32) when comparing to all perspectives. The highest score was physical quality of life  ( = 3.61, S.D.= 1.01) With regard to the predictive factor of quality of life, marital status, relationship in family, performing exercise, period of diabetes, period of hypertension, controlled diabetes mellitus and hypertension, and complication of diabetes and hypertension were statistically significant with levels of quality of life    (p≤ .001-.05, r2 = .70). The effect of these predictors on quality of life was .70 (r2 = .70).  
For qualitative results: The qualitative data was categorized to be three themes that were         1) the perception of diabetes mellitus and hypertension included diabetes mellitus and hypertension being chronically illness, diabetes mellitus and hypertension being caused by unhealthy behavior, and diabetes mellitus including dry and wet symptoms, 2)  quality of life of diabetes mellitus and hypertension patients included levels of quality of life in diabetes mellitus and hypertension patients being moderate levels, diabetes mellitus and hypertension affecting physical aspect of the patients, diabetes mellitus and hypertension leading the patients to have morbidity, suffering from diabetes mellitus and hypertension having to dependent family member, and caring from health care providers can help the patient to be better 3) methods to improve quality of life included patients with diabetes mellitus and hypertension could have good quality of life by diet control, doing exercise, medication compliant, emotional management, self - management, good caring from health care provider and alternative medicine could help the patient to increase quality of life.