Objectives: Levodopa-carbidopa intestinal gel infusion (LCIG) is indicated in patients with advanced levodopa-responsive Parkinson's disease (PD) for the treatment of motor fluctuations and dyskinesias. Here we describe 4 PD patients who developed disabling diphasic dyskinesias after LCIG initiation. Methods: The clinical data of 33 PD patients consecutively treated with LCIG therapy were obtained through direct clinical observation and detailed review of medical records. Results: Within 10 days, after LCIG introduction, we identified 4 subjects (12.1%) with persistent and disabling diphasic dyskinesia (DD). We tried to manage these symptoms by increasing morning LCIG flow and adding "extended-release" formulations of dopamine-agonists and levodopa/carbidopa during bedtime. Within 1 month, all patients presented a gradual reduction in the duration and severity of DD. Conclusions: To our knowledge, this is the first report describing the occurrence of DD in a small cohort of advanced PD patients after LCIG initiation. We wish to draw the attention of clinicians to the risk of developing disabling DD in PD patients switched to the LCIG monotherapy. (C) 2017 Elsevier Ltd. All rights reserved.