The abundance and composition of the mesozooplankton were studied in the upper 100 m of the northern Gulf of Aqaba over a period of 22 months between February 2002 and December 2003. The samples were collected monthly with a Nansen net of 200 μm mesh size. The abundance of total mesozooplankton ranged between 245 and 3065 ind. m⁻³. Highest densities in 2002 were recorded in spring (March/April) and in autumn (October/November), while several peaks occurred in 2003 with maximum abundance in early summer (June/July). Copepods dominated the mesozooplankton community during the whole sampling period (~79%), followed by mollusc larvae (8%), appendicularians (2.5%) and chaetognaths (2.4%). Within the copepods, calanoids were predominant throughout the sampling period (41–83%). Cyclopoid copepods accounted for 17 to 59%, while harpacticoids occurred only in very low numbers (<1%). Within the calanoid copepods, Clausocalanidae, Paracalanidae and Acartiidae were abundant, accounting for 84 to 98% of the calanoids.