Purpose: We performed a survey of Israeli oncology patients to examine the extent of their use of complementary therapies (CT) and to compare sociodemographic, psychologic, and medical characteristics, attitudes, and quality of life of users and nonusers of CT. Patients and Methods: Questionnaires were administered to 1,027 patients attending ambulatory and inpatient hematology or oncology facilities at three hospitals. Medical information was extracted from charts. Univariate and multivariate comparisons of users and nonusers of CT were performed. Results: A total of 526 participants (51.2%) had used CT since their diagnosis, and 357 patients (34.9%) had used CT recently (in the past 3 months). Factors that multivariate analysis found to be significantly associated (P < .05) with recent CT use were as follows: female sex; age 35 to 59 years; more education; coming to the hospital by private car; advanced disease status; having a close friend ora relative with cancer; and attending support groups or individual counseling. After controlling for these factors, individually examined psychosocial variables associated with recent CT use included the following (odds ratios [OR] with 95% confidence intervals [CI]): needs unmet by conventional medicine (OR, 2.76; 95% Cl, 1.95 to 3.89); helplessness (OR, 1.39; 95% Cl, 1.0 to 1.91); incomplete trust in the doctor (OR, 1.49; 95% Cl, 1.08 to 2.06); and changed outlook or beliefs since the diagnosis of cancer (OR, 1.47; 95% Cl, 1.07 to 2.02). Functional quality of life (including physical, emotional, social, and role function) and symptom (fatigue and diarrhea) scores were significantly worse for recent CT users compared with nonusers, controlling for age, sex, and current disease status. Conclusion: Characteristics associated with CT use include age, sex, education, and advanced disease. Significant associations between CT use and attending supportive psychotherapy, unmet needs, helplessness, and worse emotional and social function indicate considerable distress, suggesting that increased attention to psychosocial needs within oncologic settings is warranted.