As survival of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) increases and the number of patients who live long rises, health-related quality of life (HRQoL) becomes a relevant endpoint. Few studies investigated this, mainly as a secondary endpoint in randomized clinical trials where patients with early stage CLL/SLL, and elderly/frail patients were underrepresented. The aim of our study was to assess HRQoL in a population-based setting, including these previously underrepresented patients. Out of 175 patients diagnosed with CLL/SLL between 2004 and 2011, 136 (78 %) returned the HRQoL questionnaire. The outcomes were compared to an age- and sex-matched norm population. Detailed data on stage and treatment were extracted from a population-based hematological registry (PHAROS). Patients ever treated for CLL/SLL reported significantly poorer HRQoL than the norm population (p < 0.01 with large clinically important differences. Interestingly, no differences were observed between the norm population and patients under active surveillance. In contrast to our hypothesis, patients treated with chlorambucil reported the lowest HRQoL scores. Drastic, long-lasting negative effects of starting treatment on HRQoL cannot be excluded, whereas active surveillance does not seem to provoke worrying, anxiety, or depressive symptoms. Further elaborate research into the impact of starting therapy on HRQoL is needed, especially in patients that are underrepresented in most clinical trials, and thoroughly consider its results during revision of treatment guidelines.