Introduction: Systemic Lupus Erythematosus (SLE) is a chronic inflammatory autoimmune disease of unknown cause without specificity for a particular organ. Juvenile SLE (jSLE) affects a greater number of organs and systems and presents a more aggressive clinical course than in adults. Hematological alterations could be presented as the only manifestation of SLE, so a detailed and systemic approach should be performed in these patients, once other causes such as infections and neoplasms have been excluded. objectives: To determine the hematological compromise in patients diagnosed with jSLE in the Pediatric Service of the Faculty of Medical Sciences of the National university of Asunción; over a period of 5 years. Materials and Methods: Retrospective, observational, descriptive, cross-sectional study. Non-probability sampling of consecutive jSLE cases diagnosed or under follow-up from January 2012 to May 2017. Results: Of the 73 patients, 57 women (78%) and 16 (22%) men were found, with an F:M ratio of 3.5:1. Average age at diagnosis was 11.9 years (SD: 3.65, range between 2 and 17 years). Regarding origin, 39 patients (53%) came from the Capital and Central Department and 34 cases (46%) from rural areas. The mean time between onset of symptoms and clinical diagnosis was 2 months (SD 1.27 months). Symptoms at first consultation were: arthralgias in 38 patients (52%), fever in 14 cases (19.2%), cutaneous-mucosal manifestations in 10 patients (13.7%), neurological manifestations in 5 cases (6.8%), edema in 4 patients (5.5%) and constitutional manifestations in 2 patients (2.7%). Hematologic abnormalities were found in 62 patients (85%), with a single series affected in 25 cases (40.3%), bicytopenia in 33 patients (53.2%), and pancytopenia in 4 patients (6.5%). The most frequent alterations were: anemia in 58 patients (79.4%), lymphopenia in 27 cases (36.9%), thrombocytopenia in 21 patients (28.4%) and leukopenia in 17 cases (23.2%). 60% of patients had more than one affected series. On the subject of anemia (n=58), 16 patients (27.6%) had a direct positive Coombs test and 42 patients (72.4%) had a direct negative Coombs test. Concerning hematimetric indices, 40 patients (69%) presented normochromic normocytic anemia and 18 patients (31%) hypochromic microcytic anemia. Conclusion: Hematological alterations were a frequent finding as a initial manifestation of SLE. Most cases had involvement of two series, with non-hemolytic anemia being the predominant finding. Laboratory tests are of great value when evaluating a patient with suspected autoimmune disease, since the results can confirm the diagnosis, estimate the severity of the disease, assess the prognosis and monitor SLE activity.