Introduction: Epilepsy is a chronic neurological disorder that challenges neurologists in diagnosis and treatment. Electroencephalogram (EEG) has adjunctive value in epilepsy diagnosis. Its presentation is usually asymptomatic, where EEG might show characteristic epileptiform discharges. Routine inter-ictal EEG suffers from poor sensitivity, spatial resolution and inter-observer reliability. The seemingly-normal background EEG can be quantitatively analyzed to find marker of the disease. Objective: To compare the frequency parameters in background EEG of adult epileptic patients with healthy controls. Methods: Twenty-seven epilepsy cases and forty-two apparently healthy controls were selected using convenient sampling method. Comorbidities like encephalopathy were excluded. EEG was recorded by 19-channel scalp EEG machine using 10-20 system. Eleven channels were band-filtered at 1-30 Hz window, and five-second epochs of background waves selected at resting eye-closed and hyperventilated states. Spectral power was computed using Fast Fourier Transform (FFT). Absolute power (AP), relative power (RP) and Shannon spectral entropy (SSE) were compared between cases and controls. Results: Anthropometric, cardiorespiratory variables and posterior dominant rhythm frequency were comparable between the groups. On quantitative analysis of background waves in resting state, cases (n=27) had significantly higher AP than controls (n=42) globally, notably in delta [12.06 (7.03-18.08) vs 6.65 (4.17-10.16), p=0.002 at F7; 6.77 (5.42-13.66) vs 5.96 (4.29-7.49), p=0.04 at P4; 10.43 (6.60-16.50) vs 6.16 (4.07-8.92), p=0.002 at Cz]; and theta [4.27 (2.77-13.09) vs 1.77 (1.37-2.50), p<0.001 at F7; 5.65 (2.92-14.99) vs 2.25 (1.36-4.11), p<0.001 at P4; 7.32 (3.11-16.33) vs 3.14 (1.88-4.16), p=0.001 at Cz] (Wilcoxon Rank-sum test). In RP, cases had higher power in theta band globally [e.g., at F7, 0.15 (0.10-0.21) vs 0.09 (0.06-0.13), p<0.001]; whereas it was less at F7 in beta [0.10 (0.05-0.15) vs 0.14 (0.09-0.18), p=0.01] and at Cz in alpha band [0.36 (0.20-0.53) vs 0.47 (0.26-0.66), p=0.04] (Wilcoxon Rank-sum test). Comparison during hyperventillation showed similar differences between the groups [e.g., delta AP of 12.9 (8.50-22.12) vs 7.55 (5.06-11.84), p=0.003 at F7]; except for delta AP at Cz, F3 and P3 (Wilcoxon Rank-sum test). The effect of hyperventillation in resting EEG was a significant increase in spectral power of controls at lower frequency bands compared to resting state, notable in Cz [AP of 7.94 (5.70-10.40) vs 6.16 (4.07-8.92), p=0.004 and RP of 0.30 (0.21-0.42) vs 0.24 (0.15-0.33), p=0.001, in delta]; which was not seen in cases [AP of 9.80 (6.10-19.9) vs 10.4 (6.60-16.5), p=0.46 and RP of 0.31 (0.21-0.37) vs 0.26 (0.17-0.36), p=0.96, in delta] (Wilcoxon Signed-Rank test). In most comparisons, SSE and RP showed similar trend of changes. Conclusion: The background EEG of epileptic patients showed higher spectral power at low frequency in most of the scalp sites, along with decrease in relative power at higher frequency; indicating slowing of the brainwaves. The expected effects of hyperventillation in EEG was less in patients than controls. These findings can be utilized for detecting epilepsy from background EEG.