This article assesses the relative importance of several factors believed to reduce the likelihood of health insurance coverage among working Latinos in California, including cost, immigration history, availability of insurance, beliefs about insurance, and beliefs about health and health care. According to a survey of 1,000 randomly selected adults, the most prominent factors contributing to working Latinos' lack of health insurance include low income, absence of or ineligibility for a plan at work, birth outside the United States, and recent immigration. Although the availability of affordable plans plays a predominant role, the importance of potentially inaccurate perceptions of the cost of health insurance and unidentified factors associated with recent immigration may also be important in some segments of the population. Maintenance and redesign of employer-provided or public insurance programs seem essential for increasing health insurance among working Latinos, as may be encouragement of low-cost clinics in some Latino communities.