The aim of the presented study is to specify essential predictors that co‑determine the manner in which patients deal with chronic diseases and that constitute personal resources affecting the quality of life during the difficult time of illness. Apparently, studies regarding patients representing five groups of chronic diseases indicate unambiguously that optimism and the sense of self‑efficacy are factors which highly differentiate examined persons divided according to the assessment of their quality of life. Contrary to pessimism and lack of confidence in one’s own agency, optimism and the sense of self‑efficacy support health‑oriented and disease prevention behaviors and, in the event of illness, actively participate in the treatment process and increase the hope level regarding the prognosis. Optimists, both healthy and ill, better assess the quality of their lives and the sense of self‑efficacy in the examined persons increases significantly with an increasing assessment of the quality of life. The levelof optimism and the sense of self‑efficacy are affected neither by the duration of illness nor the patient’s age. The optimism level slightly decreases in patients in the first few years of illness, but later it goes back to the level seen in healthy persons. Statistically insignificant differences related to the assessment of self‑efficacy concern patients with ischemic heart disease whose sense of self‑efficacy is the highest. Patients with asthma have the lowest sense of self‑efficacy.