Background: ICIs are associated with irAEs. We describe the incidence of irAEs in patients with solid tumors receiving ICIs and its correlation with efficacy. Methods: We retrospectively analyzed all patients with solid tumors receiving ICIs in our center. IrAEs were graded according CTCAE v4.0. Kaplan Meier and log-rank tests were used to evaluate progression-free (PFS) and overall survivals (OS). Analyses were performed using SPSS v24 package. Results: From March 2014 to January 2018, 178 patients received ICIs. Median age was 64.1 [33-88] years, 72% were male. Most frequent tumors were lung (63.5%), bladder (14.6%) and melanoma (11.8%). 96% presented advanced disease. Most common used ICIs were nivolumab (38.2%), pembrolizumab (28.7%) and atezolizumab (17.4%). ICIs were used as monotherapy (74.7%) or in combination with ICI (3.4%), chemotherapy (17.4%) or targeted therapies (4.5%). Median duration of immunotherapy was 6.9 [0.7-46.3] months. 95 (53.4%) patients developed 158 irAEs with a median number per patient of 1.2 [0-4]. Most frequent irAE was rash (24.7%) followed by diarrhea (17.7%), hypothyroidism (9.5%), arthritis (6.9%), hyperthyroidism (3.8%), pneumonitis (3.2%) and mucositis (3.2%). Median time to the onset irAEs was 53.2 [11-490] days. 12 (6.7%) patients presented grade (G) 3-4 irAEs: 5 G-3 diarrhea, 2 G-3-4 liver dysfunction, 1 G-3 pneumonitis, 1 G-3 hypopituitarism, 1 G-3 mucositis, 1 G-3 arthritis and 1 G-3 nephritis. There were 2 (1.1%) treatment-related deaths due to pneumonitis. 21.3% patients required steroids for irAEs management. 8.4% patients discontinued treatment due to irAEs. 73.9% irAEs had improved at the time of analysis. OS was superior in patients with advanced disease experiencing irAEs: 37.3 [95%CI, 19.2-51.4] vs 7.8 [95%CI, 4.9-10.8] months (p< 0.0001). Similarly, PFS was longer: 7.9 [95%CI, 4.4-11.4] vs 2.6 [95%CI, 2.0-3.2] months (p< 0.0001). Conclusions: There was a significant correlation between presence of irAEs and outcomes in patients with advanced solid tumors treated with ICIs.