This study surveys the optical and microphysical properties of high (ice) clouds over the tropics (30°S-30°N) over a 3-year period from September 2002 through August 2005. The analyses are based on the gridded Level-3 cloud product (Collection 4) derived from the measurements acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard both the NASA Earth Observing System Terra and Aqua platforms. The cloud products provide daily, weekly, and monthly mean cloud fraction, cloud optical thickness, cloud effective particle size, cloud top temperature, cloud top pressure, and cloud effective emissivity (defined as cloud emittance multiplied by cloud fraction). The focus of this study is on high-level ice clouds. We classify the MODIS-derived high clouds as cirriform and deep convective clouds using the International Satellite Cloud Climatology Project (ISCCP) classification scheme. Cirriform clouds comprise more than 80% of the total high clouds, whereas deep convective clouds account for less than 20% of the total high clouds. High clouds are prevalent over the Intertropical Convergence Zone (ITCZ), the South Pacific Convergence Zone (SPCZ), tropical Africa, Indian Ocean, and tropical and South America. Furthermore, land-ocean, morning-afternoon, and summer-winter variations of high cloud properties are also observed.