Cathy Ling was a human female serving in the Federation Starfleet in the late 24th century.

In 2376, Ensign Ling served aboard starbase Deep Space 9. During the Gateways crisis, she was assigned to the runabout, USS Euphrates with Colonel Kira Nerys, but was replaced by the Jem'Hadar observer Taran'atar at the last minute. Instead, she remained on the station, serving in Ops under the command of Lieutenant Ezri Dax. Ling noticed that while talking to Vedek Eran Dal, Dax's voice changed-getting deeper and scratchier-as she unwittingly tapped into Curzon Dax's experience as an ambassador. (DS9 - Gateways novel: Demons of Air and Darkness)

Starbase Deep Space 9 personnel and residents
Station personnel	K. Adabwe • Ahzed • Aleco V. • Alle T. • Amran • T. Ane • N. Aponte • J.S. Bashir • Battes A. • S. Bowers • Cardok • Cenn D. • Chavez • Cryan • E. Dax • J. Dax • Devro • M. Eddington • Eddon • Etana K. • Gaysd T. • Girani S. • Goodman • Gordimer • Guerette • Hage • Hava • T. Jast • Jataq'qat • S. Jonsson • Kabo • Kahrimanis • Kelly • Kira N. • Kurn • C. Ling • P. Matthias • McCormick • McEwian • K. Merimark • Monyodin • Moru • I. Muckerheide • Munson • J. Si Naran • Nedani I. • Nguyen • Nog • M.E. O'Brien • Occino • Odo • D. Parks • Pertwee • Phongsit • G. Primmin • Redac • K. Richter • Ro L. • Rom • G. Roness • Sanger • Selzner • J. Senkowski • Setrin Y. • Shul T. • B.L. Sisko • N. Sthili • M. Strang • S. Tarses • P. Tenmei • Terek • T. ch'Thane • Tolland • M. Tomson • T'Peyn • Trulli • E. Vaughn • Vu K. • Wasa G. • Wayeh S. • D. Wilkens • Worf • Woros K.
Station residents	Broik • Chram • Conpap • Elvim • Frool • Gann • E. Garak • Grehm • Grimp • Jas-qal • Kaga • Leeta • Modo • Morn • Nog • K. O'Brien • M. O'Brien • K. O'Brien • Quark • Rom • J.I. Sisko • Sorv • Taran'atar • Tora Z. • Treir • Vissh • K. Yates • Yelsi