Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune disorder of the peripheral nervous system. Diagnosis relies on clinical and electrophysiological criteria. Various disorders requiring specific treatment regimens may be associated with CIDP, including sarcoidosis (SAR-CIDP) and connective tissue disease (CTD-CIDP). Therefore, it is important to distinguish between CIDP, SAR-CIDP and CTD-CIDP. In this retrospective monocentric study, we analyzed 16 patients with SAR-CIDP and 11 with CTD-CIDP and compared them with a group of 17 patients with idiopathic CIDP. SAR-CIDP patients had a frequently acute or subacute CIDP onset. CTD-CIDPs were mostly Sjögren’s syndrome and lupus, and patients had a chronic onset. An older age at onset (64.5 vs. 54 years,p= 0.04), more atypical presentation (19/25 (76%) vs. 6/17 (35%),p= 0.008), acute/subacute onset of symptoms (15/25 (60%) vs. 1/17 (6%),p= 0.0004) and more frequent weight loss (7/16 (44%) vs. 0/17 (0%),p= 0.017) were identified SAR-CIDP and CTD-CIDP groups. Response to intravenous immunoglobulin therapy was lower in the combined SAR-CIDP and CTD-CIDP group (44% versus 82%,p= 0.005). As sarcoidosis and CTDs might be associated with CIDP and require specific management, the “red flags” mentioned above should be kept in mind by clinicians managing patients with CIDP.