The ignition delay times (IDT) were measured for the rocket propellant-1 (RP-1) in a shock tube at low-pressure conditions. The measurements were carried out behind the reflected shock wave for the premixed gaseous mixture of RP-1/oxygen/argon over a temperature range of 1135.80–1424.55 K, a pressure range of 0.35–2.75 bar, and at the equivalence ratios \((\phi)\) of 0.5, 1 and 2. The ignition delay time was determined using the pressure and CH emission (431 nm) signals obtained at 5 mm from the end wall of the driven section of the shock tube. The ignition delay time of RP-1 was observed to be maximum at an equivalence ratio of 1 at studied pressure and temperature conditions. It was also observed that the pressure dependence of the ignition delay time of RP-1 varies with the equivalence ratio, and it is maximum for the equivalence ratio of 1. The Arrhenius form of correlation was developed for the ignition delay time as a function of pressure and temperature. Also, a comparison was made between the ignition delay time data at high pressure, available in the literature, and the low-pressure data obtained in this study.