Purpose: We explored whether severe or critical hypotension can be predicted, based on patient and resuscitation characteristics in out-of-hospital cardiac arrest (OHCA) patients. We also explored the association of hypotension with mortality and neurological outcome. Materials and methods: We conducted a post hoc analysis of the TTH48 study (NCT01689077), where 355 out-of-hospital cardiac arrest (OHCA) patients were randomized to targeted temperature management (TTM) treatment at 33 °C for either 24 or 48 h. We recorded hypotension, according to four severity categories, within four days from admission. We used multivariable logistic regression analysis to test association of admission data with severe or critical hypotension. Results: Diabetes mellitus (OR 3.715, 95% CI 1.180–11.692), longer ROSC delay (OR 1.064, 95% CI 1.022–1.108), admission MAP (OR 0.960, 95% CI 0.929–0.991) and non-shockable rhythm (OR 5.307, 95% CI 1.604–17.557) were associated with severe or critical hypotension. Severe or critical hypotension was associated with increased mortality and poor neurological outcome at 6 months. Conclusions: Diabetes, non-shockable rhythm, longer delay to ROSC and lower admission MAP were predictors of severe or critical hypotension. Severe or critical hypotension was associated with poor outcome.