We will present a new characterization of mid-level clouds using combined active and passive remote sensing techniques from A-Train satellites, including CALIPSO and CloudSat, and ARM ground-based observations. First, we will test the sensitivity of mid-level cloud frequency of occurrence to different ways of defining where the mid-level is. Specifically, we will see how perturbations to the traditional definitions of the mid-level as occurring between cloud top pressures of 680 and 440 hpa or cloud top heights between 3 and 7 km affect mid-level (and high and low) cloud frequencies. These tests will be performed both in the Tropical Western Pacific region and globally. In addition, the usefulness of cloud top temperature as a midlevel cloud definition will be investigated. The new characterization including cloud boundaries, cloud top pressure and temperature will be demonstrated for single- and multi-layered cloudy scenarios separately. The likelihood of the occurrence of mid-level clouds in multi-layered cloud systems, which can result in serious biases in characterizing mid-level clouds, will also be evaluated.