This study evaluated whether serum lactate levels (SLL) at admission in patients with cardiac arrest (CA) can predict successful return of spontaneous circulation (ROSC) or short-term survival, especially within the first 24 h. This prospective, observational study was conducted in the emergency department (ED) of a training and research hospital from April 2015 through February 2016. It included all patients older than 18 years who presented to the ED during the study period with non-traumatic out-of-hospital cardiac arrest (OHCA). The study measured two outcomes: whether ROSC was achieved and whether short-term survival was achieved. ROSC was defined as the presence of spontaneous circulation for the first hour after cardiopulmonary resuscitation (CPR). Survival was defined as having survived for a minimum of 24 h after ROSC. The study included 140 patients who were admitted to the ED with OHCA. ROSC was achieved in 55 patients (39.3%), and survival for 24 h following CA was achieved in 42 patients (30%). The mean SLL in the ROSC (+) and ROSC (-) groups were 9.1 ± 3.2 mmol/L and 9.8 ± 2.9 mmol/L, respectively. The mean SLL in the survivor and non-survivor groups were 8.6 ± 2.9 mmol/L and 10 ± 3.1 mmol/L, respectively. These differences were not statistically significant (p = 0.1). A multivariate regression model assessing the factors that predicted both ROSC and 24-h survival showed the odds ratio (OR) of initial SLL was 1.3 (95% CI: 1.05-1.6) and 1.1 (95% CI: 0.9-1.3), respectively. This study showed that in OHCA patients, SLL on admission was not associated with increased ROSC achievement or 24-h survival.