WASHINGTON'S cab drivers have a serious complaint that deserves quick official attention. They are in urgent need of a fare increase to meet rising gasoline costs.

One of the more misguided and fortunately unsuccessful attempts to draw attention to this fact was a call by some drivers for a two-day strike. But thanks to the notorious disorganization of the city's cab drivers, the inconvenience to a helpless riding public was minimal. Still, the case for relief is obvious. With jumps in local gas prices of as much as 40 percent since January, drivers are taking a financial beating. The only fare increase they have been granted since January added a dime to the basic ride, no matter how many miles the ride may be.

This means that, for a four-zone ride, the driver's only increase this year has been a pittance - about 3 percent. The D.C. Public Service Commission, which has authority over fares, has indicated that some increase is in the offing, but so far there's been no word on when or how much - only that "studies" of drivers' expenses are under way.

In the long run, Washington's taxi fare structure probably should be overhauled, perhaps to include a switch to meters or some other method of including time spent as well as distance covered. Certainly such major revisions should await comprehensive hearings, since there is wide disagreement among drivers about meters. But right now, and for now, the city's cabbies deserve an immediate, realistic response to the increased costs they are facing at the pumps.