Aim To assess the effectiveness of intravitreal dexamethasone implants for treating postsurgical macular oedema (PSMO) including Irvine-Gass syndrome and determining the predictive factors of treatment response. Methods Descriptive, observational, retrospective, consecutive, uncontrolled, multicentre, national case series. One hundred patients were included between April 2011 and June 2014, with a minimum of 1-year follow-up. Patients received dexamethasone implant 0.7mg at baseline. Clinical characteristics, best-corrected visual acuity (BCVA), central subfield macular thickness (CSMT) and intraocular pressure were measured at each visit. The main outcome measure was the change in BCVA (Early Treatment of Diabetic Retinopathy Study (ETDRS) letters: L). An analysis of predictive factors of treatment response is also provided. Results Mean improvement in BCVA was 9.6 (10.6) L at month 6 and 10.3 (+/- 10.7) L at month 12 (p<0.001). The proportion of eyes with gains in BCVA of 15 or more letters was 32.5% and 37.5% at months 6 and 12, respectively. The mean reduction in CSMT was 135.2 and 160.9 mu m at months 6 and 12, respectively (p<0.001). Thirty-seven per cent of patients did not need a second injection after the first injection during follow-up. The presence of at least one PSMO risk factor decreases the probability of a gain in visual acuity (VA) 10 L (p=0.006). Initial VA 50 L at baseline and non-naive status decrease the probability of having only one injection during follow-up (p=0.044). Conclusions The significant gain in BCVA from baseline achieved at month 6 was maintained at month 12 after intravitreal injection of dexamethasone implant. Naive status seems to be a good predictive factor of treatment response.