The first reports of COVID19 disease don’t highlighted associated Acute Kidney Injury (AKI) but later there have been more evidence that viral load in the kidney it’s secondary only to his tropism for the respiratory system yet the rate of AKI and the associated outcomes are not well understood. AKI often occur concurrently to respiratory failure; risk factors are: need for ventilation, vasopressor use and sepsis. Need for RRT ranging from 26 to 45 % and patients (pts) mechanically ventilated who received RRT had a poor prognosis: survival varies from 20 to 40 %. COVID19 pts have a hyper-inflammatory state and AKI is final common pathway of an increased immunologic response leading to systemic inflammation due to uncontrolled circulating levels of pro-inflammatory mediators and cytokine induced direct organ damage. HDx represents an innovative strategy able to remove inflammation soluble mediators. It's cause a markedly reduction of pro-inflammatory cytokines transcription induced by peripheral neutrophil activation with decrease of ROS, TNF-α and IL-6 production and increase of apoptosis. Aim of this study is to determine incidence and outcome of AKI in critically ill Covid19 pts and the role of HDx. In a retrospective observational study, we evaluated development of AKI in 95 consecutive COVID19 pts admitted in the ICU of our COVID HOSPITAL from November 2020 to May 2021. All received mechanical ventilation. AKI pts requiring RRT, for logistical reasons were treated random with daily IRRT: HF-HD (3 pts-FX80, FMC) and HDx therapy (9 pts-THERANOVA 400, Baxter). Both treatments ranging from 1 to 5 sessions for each patient. They were daily assessed using the following: urea, creatinine, C-reactive protein (CRP), procalcitonin (PCT), D-Dimer. Need for vasopressor, BMI and outcome are also evaluated. The values have been reported as mean ±SD. AKI was defined according to KDIGO. Among the 95 pts the mean age was 70.4 ±16 years, 73 were male (76.8%). All were hypertensive, over 30% were obese, 20% with nephropathies, some with diabetes or COPD. AKI developed in 39 pts (41%) and 12 of them (30.7%), mostly obese, underwent IRRT by HDx: Qb=195 ±15.8 ml/m, TT 283.7 ±67.7 m' or HF-HD: Qb= 200 ±17 ml/m, TT 278 ±63 m'. HDx discovered a significant reduction for urea, CRP and PCT unlike HF-HD. (Tab. 1) Pts cardiovascular instability increased significantly with both types of treatments, in many cases causing their interruption even if treatments were long and with minimal hourly ultrafiltration. None of those undergoing haemodialysis survived; in particular, obese had the worst intradialytic compliance and the shortest survival. Early onset RRT does not alleviate mortality. In our experience AKI complicated the course of more than 1 in 3 critically ill COVID19 pts: theirs risk for AKI was higher than the general ICU population. HDx had a significant impact on inflammation and renal markers, compared to HF-HD, for his increased clearance of cytokines. Unfortunately, COVID19 pts who received RRT had a poor prognosis, especially if obese and if requiring high doses of vasopressors, regardless hemodialysis techniques: intermittent or continuous, because its known that all are equally efficient. Since COVID-19 remains a threat to public health in the near future, hopefully further factors that may impact AKI and survival in these pts will be clarified.