Limbic encephalitis is a potentially treatable immunological condition. The presence of voltage-gated potassium channel antibodies (VGKC-Ab) in the CSF and serum of patients with the condition is a marker of the disease associated with a non-paraneoplastic form and good response to treatment. Recent work has highlighted absent serum VGKC-Ab and distinct immunology in patients with the paraneoplastic form of limbic encephalitis. Here, we describe four patients with the typical clinical presentation, neuropsychological features and brain imaging of acute limbic encephalitis, in the absence of any evidence for associated cancer during follow up of at least 18 months. The patients all had negative testing for VGKC-Ab measured during their acute presentation. All patients made some recovery although all were left with significant cognitive deficits and persistent seizures. These cases demonstrate that the absence of VGKC-Ab in limbic encephalitis does not necessarily imply a paraneoplastic form. Further work is required to establish the immunological basis for the disorder in these cases, and the optimal treatment regime.