I analyze how general practitioners (GPs) indirectly affect their patients' employment outcomes by deciding the length of sick leaves. I use an instrumental variables framework where spell durations are identified through supplyside certification measures. I find that a day of sick leave certified only because the worker's GP has a high propensity to certify sick leaves decreases the employment probability persistently by 0.450.69 percentage points, but increases the risk of becoming unemployed by 0.280.44 percentage points. These effects are mostly driven by workers with low job tenure. Several robustness checks show that endogenous matching between patients and GPs does not impair identification. My results bear important implications for doctors: Whenever medically justifiable, certifying shorter sick leaves to protect the employment status of the patient may be beneficial.