Atypical hemolytic uremic syndrome (aHUS), more commonly known as complement-related HUS is a kind of thrombotic microangiopathy (TMA) characterized by inherited pathogenic variants in complement genes or acquired autoantibodies against complement factors, predominantly involving kidney [1]. Activation of the alternative complement pathway (AP), which occurs due to dysfunction in complement regulatory proteins or, less commonly, activation of mutations in the complement proteins themselves, constitutes the pathogenesis of aHUS and enables endothelial damage [2]. It may also present as secondary aHUS triggered by COVID-19, Shiga toxin-producing Escherichia coli, or other identifiable conditions [1]. As a triad for the diagnosis of aHUS; thrombocytopenia, microangiopathic hemolytic anemia (MAHA), and acute kidney injury are used, however, there is no universally accepted diagnostic criterion and it is considered inadequate because it is established without even histological findings in the kidney [1]. Complement factor H (CFH), complement factor I (CFI), membrane cofactor protein (MCP, CD46), thrombomodulin, complement factor B (CFB), and complement 3(C3) mutations are the mutations that play a dominant role in the pathogenesis of aHUS [2,3]. In 30% to 40% of patients who respond to complement inhibition, these mutations are not detectable or have genetic variants of unknown significance [2]. In a patient presenting with TMA findings, thrombotic thrombocytopenic purpura (TTP) must be excluded by showing that ADAMTS13 activity is above 10%. Short-acting C5 blockade (eculizumab) should be initiated without delay in those with ADMTS13 levels above 10% and those with severe oliguric acute renal failure [1]. Stool sampling should be done in individuals with diarrhea to detect Shiga toxin and/or microorganisms that produce Shiga toxin. Ravulizumab is a long-acting C5 inhibitor that is considered safe and effective in both treatment-naive adult and pediatric patients and in pediatric patients who have previously received complement inhibition [4]. Ravulizumab's half-life is four times longer than eculizumab (∼51.8 days vs. ∼11 days) and offers a reduced dosing frequency of up to 4-8 weeks instead of every 2-3 weeks [5]. All patients receiving complement inhibitors should be included in the vaccination program for Neisseria meningitis, Streptococcus pneumonia, and Haemophilus influenza type b, and early signs of infection should be carefully monitored and necessary parenteral antibiotic therapy should be started without delay. Although plasma exchange (PEX) treatment can provide partial benefit, especially in those with CFH, C3, and thrombomodulin gene variants, it has now been replaced by complement inhibitors where available. PEX treatment response is insufficient in CFI variants and does not provide additional benefits to complement inhibitors in MCP (CD46) deficiency [6]. Kidney transplantation treatment is associated with a high risk of recurrence, especially in patients with CFH mutations. However, the post-transplant relapse rate decreased with eculizumab treatment[7]. Iptacopan is an orally available, highly potent proximal complement inhibitor that specifically binds to CFB, the primary driver of the disease, thereby inhibiting AP [8]. Other treatments are being investigated, including alternative pathway-blocking agents and lectin pathway inhibitors.