Results are described from observations of submm CO emission from isolated young stars with an infrared excess. These include both Vega‐excess and isolated Herbig AeBe stars, ie those at the transition between the formation stage and the main sequence. Of those detected, more than 60&percent; show double‐peaked profiles, interpreted as emission from rotating gas disks. The spectra of three objects are compared with a basic disk model. HD 141569 has evidence of a double‐ring gas structure, with radii of 90 and 250 au — similar to that seen in scattered light. MWC480 has an asymmetric line shape, interpreted as a non‐axisymmetric disk temperature distribution. Finally the debris disk HD 9672 shows a broad line from a relatively compact disk or ring.This molecular gas is found in stars of ages up to 10–20 Myr, and its’ removal from the disk signifies the end of the accretion and the start of the collision‐dominated phase of disk evolution. © 2004 American Institute of Physics