Petersen

MEMORANDUM *

Social Security disability benefits claimant Barbara J. Petersen appeals the district court’s affirmance of the Commissioner’s denial of benefits. We reverse and remand.

I.

The ALJ first erred by improperly rejecting Petersen’s treating neurologist’s retrospective diagnosis. In 1999, Dr. Wambaugh diagnosed Petersen as having had multiple sclerosis (“MS”) since at least 1991. The ALJ failed to credit Dr. Wambaugh’s diagnosis by concluding that Petersen had only “possible multiple sclerosis.”

The opinion of a treating physician “can only be rejected for specific and legitimate reasons that are supported by substantial evidence in the record.” Lester v. Chater, 81 F.3d 821, 831 (9th Cir.1995). The ALJ’s only stated reason for rejecting Dr. Wambaugh’s diagnosis is that it was rendered retrospectively. It is well established in this circuit that such a rationale is legally insufficient. See, e.g., Morgan v. Comm’r, 169 F.3d 595, 601 (9th Cir.1999); Lester, 81 F.3d at 832 ; Flaten v. Sec’y of Health & Human Servs., 44 F.3d 1453 , 1461 & n. 5 (9th Cir.1995); Smith v. Bowen, 849 F.2d 1222, 1225 (9th Cir.1988). Because the ALJ failed to provide a legitimate reason for his…