Camptocormia is an abnormal truncal flexion posture that occurs while walking or standing. It is usually caused by various hypokinetic movement disorders such as Parkinson disease and multiple system atrophy. Myopathy or motor neuron disease can also be infrequent causes of camptocormia. Paraspinous muscle biopsy usually reveals focal myositis, regardless of the etiology of camptocormia. We describe the first case of generalized inflammatory myopathy with prominent camptocormia and proximal muscle weakness. Muscle biopsy of the quadriceps confirmed the diagnosis of polymyositis, and the posture showed modest improvement in response to steroid treatment.