DEAP-3600 is a single-phase liquid argon WIMP detector located 2km underground in the SNOLAB research facility. DEAP-3600 is searching for dark matter; an elusive form of matter that was first postulated in the early 20th century, but has not yet been found. The goal of this work is to perform a low mass WIMP search. A low mass WIMP search is made possible by lowering the energy threshold of the hardware trigger from 1000ADC to 150ADC. Low energy events in the detector are characterized as Cherenkov radiation, low energy retriggers, or high energy retriggers; all of which are background events. The final data set has a live time of 2.10 days and an exposure of 4.41×10³ kg·days using a LAr target mass of (3279±97) kg. The results from the low mass WIMP search is a WIMP-nucleon spin independent cross-section of 3.96×10⁻⁴²cm² at a 90% CL corresponding to WIMPs with mass 55 GeV/c².