Latent autoimmune diabetes in adults is a form of diabetes recently classified in 2019 by the World Health Organization in 2019 (LADA), frequently underdiagnosed in primary care(PC), with an increasing incidence of 7-14%.We describe a 68-year-old male previously diagnosed with type 2 diabetes mellitus (T2DM) three years prior. He presented in PC after two weeks of amnesia, behavioral changes, and sleepiness. Systemic physical examination was unremarkable, leading to referral to the hospital with a differential diagnosis of subacute cerebrovascular disease or frontotemporal disease. During hospitalization, he was diagnosed with autoimmune limbic encephalitis. One month later, follow-up in PC showed marked clinical improvement. Given the possible association with autoimmune processes, LADA was suspected and anti-glutamic acid decarboxylase 65(Anti-GAD65) antibodies, not previously tested at the hospital, were requested. Results revealed HbA1c 6.3%, glucose 140mg/dL, LDL45mg/dL, and Anti-GAD65 45.9 kUI/L (normal ≤4.9), confirming and reclassifying the diagnosis from T2DM to LADA. The patient currently remains active, followed closely in PC, without need for insulin therapy or hospital-based diabetes management.We often suspect LADA in our consultations when there is poor T2DM control. However, in this case, in a patient with good metabolic control, the high index of suspicion for coexisting autoimmune syndromes made the diagnosis possible.We also emphasize in this patient the importance of active surveillance from PC. Thus, in an insulin-dependent disease present from its onset in 50-70% of cases3, the early clinical approach in the described case contributed to maintaining good metabolic control from PC and greater pancreatic reserve without the need for insulin therapy. Furthermore, the presence of low levels of GAD autoantibodies, as described in the literature, is associated with a better prognosis for T2DM, as found in the described case.LADA represents a continuum between T1DM and T2DM, and can be diagnosed with an analysis from our consultations, especially when associated autoimmune conditions are present, thereby improving underdiagnosis and prognosis.LADA is a disease for which a high index of suspicion in PC, especially in the presence of other autoimmune diseases, can improve both underdiagnosis and clinical follow-up for patients.