Spontaneous native aortic valvular thrombosis is an uncommon event that usually results from cardiac catheterization, bacterial endocarditis or a hypercoagulable state. We report here on a case of native valvular thrombus that was incidentally detected as masses that caused aortic stenoinsufficiency during routine follow-up, and the patient was without any of the previously described precipitating factors. The patient underwent aortic valvular surgery for removal of the aortic valvular mass. The pathological findings of the aortic valve showed organized valvular thrombus without evidence of any tumor.