Continuous wave optically stimulated luminescence (CW-OSL) is relatively a simple technique that offers good signal to noise ratio (SNR) and involves simple instrumentation. This study reports the influence and optimization of CW-OSL parameters on minimum detectable dose (MDD) using α-Al2O3:C phosphor. It is found that at a given stimulation intensity MDD in CW-OSL mode depends on signal integration time. At lower integration times MDD is inferior. It exhibits an improvement for intermediate values, shows a plateau region and deteriorates as integration time increases further. MDD is found to be ∼127 μGy at 4 mW/cm2 stimulation intensity for integration time of 0.1s, which improves to ∼10.5 μGy for 60s. At stimulation intensity of 72 mW/cm2, MDD is 37 μGy for integration time of 60s and improves significantly to 7 μGy for 1s. •CW-OSL parameters are optimized to obtain best SNR and MDD in Al2O3:C.•MDD is found to depend on signal integration time and stimulation intensity.•With time, MDD initially improves, stabilizes then deteriorates.•At a given intensity, MDD is optimum for a certain range of integration time.