The short-term benefits of levodopa/carbidopa intestinal gel (LCIG) in patients with advanced Parkinson’s disease (PD) are well documented, but the long-term benefits are still uncertain. The aim of this study was to investigate the motor and cognitive outcome of LCIG treatment in advanced PD after a follow-up period of at least 24 months. We assessed 29 patients with advanced PD who started LCIG infusion at our centre between 2007 and 2013. Motor fluctuations, parkinsonian symptoms, activities of daily living and impact on quality of life were evaluated. We also investigated the cognitive outcome using a battery of neuropsychological tests. All adverse events were recorded. Of the 29 PD patients who initiated LCIG, 16 patients reached the follow-up evaluation (24 months), after a mean time period of 32.2 ± 12.4 months. Six patients did not fulfil the 24-month follow-up visit and were evaluated after a mean time period of 8.6 ± 5.4 months. Seven patients discontinued the treatment before the scheduled visit. “Off” time and “On” dyskinesia duration were significantly reduced. LCIG improved quality of life and non motor symptoms, despite overall unchanged total levodopa doses prior to LCIG beginning. Motor and cognitive decline were detected. A relatively high number of adverse events occurred during the follow-up, above all, technical problems with the infusion device and mild problems related with gastrostomy. There were four cases of peripheral neuropathy (PN), 2 of which were considered serious. Our data confirm that LCIG is beneficial in the long-term treatment of advanced PD patients despite a decline in cognitive functions in a subgroup of patients, probably due to disease progression. PN in patients with LCIG may be more frequent than the published date suggest.