Background Persons with hearing loss may have difficulty in speech understanding, so they need to shift more resources from other on-going cognitive tasks. This increase in cognitive resources has been referred to as an increase in “listening effort: (LE). Two research questions were addressed: (Q1) Does hearing loss increase LE? (Q2) Can hearing aid (HA) amplification improve LE? Methods This study included 55 subjects that were divided into two groups: control group (I), which consisted of 15 adults with normal peripheral hearing, and study group (II), which consisted of 40 patients with bilateral SNHL. They were subdivided into two subgroups: study subgroup (IIa), which consisted of 20 patients did not use (HAs). The study subgroup (IIb) consisted of 20 patients using unilateral or bilateral HAs. LE was measured by subjective (Speech, Spatial and Qualities of Hearing Scale (SSQ), Fatigue Assessment Scale (FAS)) and behavioral measures (dual-task paradigm test (simultaneous primary auditory task (QuickSIN test) and secondary visual task (reaction time and Stroop test)). Results Hearing loss patients showed higher fatigue scores and lower scores in SSQ than the normal hearing subjects. They also showed significantly longer reaction times (RTs) in dual conditions. No significant difference was found between patient with SNHL with and without HAs in all tests. Conclusion Patients with SNHL with and without HAs showed more LE than the normal hearing subjects (Q1). Hearing aid fitting does not reduce LE (Q2). HA users showed less listening effort in favorable listening situation (higher signal-to-noise ratio) than those who did not use HAs. Increased LE is a consequence of hearing loss which could not be measured by standard audiometric measures, so it should be considered when measuring disability in those with hearing loss.