Hippocampal theta oscillations are key elements in various behavioural and cognitive processes. Based on the dualistic theory, one can differentiate between atropine-sensitive and atropine-insensitive theta activity. Atropine-sensitive theta oscillations are substantially driven by muscarinic signal transduction. Recent findings indicate that Ca_v2.3 Ca²⁺ channels are important targets of muscarinic signalling in the hippocampus mediating plateau potential generation, epileptiform burst activity and complex rhythm generation in the septohippocampal network. To investigate the implications of Ca_v2.3 Ca²⁺ channels in hippocampal theta oscillations we performed radiotelemetric intrahippocampal EEG recordings in urethane (800 mg/kg ip.) and atropine (50 mg/kg ip.) treated control and Ca_v2.3^-/- mice followed by wavelet analysis of EEG data. Our results demonstrate, that Ca_v2.3 ablation significantly affects atropine sensitive septohippocampal theta oscillations and the temporal characteristics of theta distribution, i.e. theta architecture. Our data suggest, that Ca_v2.3 voltage-gated Ca²⁺-channels are an important factor in septohippocampal synchronization associated with theta oscillation.