The article discusses a wide range of issues related to the appearance of the right for social security connected with the outset of unemployment and partial unemployment. These are the grounds for the right for social security benefits and services. Therefore, the effectiveness of social right protection of the unemployed in Ukraine depends on the correct understanding of their legal nature. There is no legal definition of such a term as unemployment risk in the Ukrainian legislation. Instead, the known definition of unemployment as a social economic phenomenon in which some people are not able to implement their right for work and wages (remuneration) as a source of livelihood. Based on the late statistical data, the author concludes that the gradual decrease in the number of unemployed, which, however, still keeps being high – more than nine percent of the economically active working population. However, the legislation of Ukraine does not define unemployment as the basis for the appearance of right for social protection. There is a concept of unemployment insurance risk instead. These are the circumstances leading to the loss of jobs, need of financial support and social services. The author argues the imperfection of such definition and proves that person’s inability to find a job leads to employment. Thus, he has come up with his own definition of unemployment, which is a condition of an economically active able-bodied person, ready and willing to work but unable to find a job. The author delineates the risk of partial unemployment from unemployment, draws attention to the poor definition of the concept of partial unemployment and as a consequence of the inappropriate narrowing of the circle of persons who are entitled to benefits in connection with its occurrence. The author arrives at this conclusion by analyzing the legislative definition of the concept of partial unemployment as a compulsory temporary reduction of the working time stipulated by law in connection with the stoppage of production due to economic, technological and structural nature without termination of employment. Partial unemployment is expected to relate exclusively to workers employed in industrial production in connection with the reduction of working time under the circumstances that do not depend on the employee and the employer’s will, but on accidents, fires, terrorist acts, wars, natural disasters (earthquakes, storms, floods, tornadoes, etc.). These are all circumstances that lead to, or may lead to, a temporary reduction in the working time of workers in any sector of the economy, not just industry. Therefore, the right to partial unemployment benefits should be applied to all workers without exception.