Abstract. In the setting of continuous logic, we study atomless probability spaces and atomless random variable structures. We characterize κ-saturated atomless probability spaces and κ-saturated atomless random variable structures for every infinite cardinal κ. Moreover, κ-saturated and strongly κ-homogeneous atomless probability spaces and κ-saturated and strongly κ-homogeneous atomless random variable structures are characterized for every infinite cardinal κ. For atomless probability spaces, we prove that ℵ 1 -saturation is equivalent to Hoover-Keisler saturation. For atomless random variable structures whose underlying probability spaces are Hoover-Keisler saturated, we prove several equivalent conditions.