Purpose: To characterise the spike potential activity and standard transient depolarisations in the aging guinea pig prostate gland. Materials and Methods: Membrane potential recordings were made in the guinea pig stroma using conventional single microelectrode recording techniques. Results: Three type of spontaneous electrical activity were recorded within the aging guinea pig prostate gland. Out of a total of 86 successful impalements 46.5% consisted of spike potential activity, 43% consisted of slow wave activity and standard transient depolarisations contributed 10.5%. Spike potentials were classified as hyper-active (frequency ≥15min^-1) or active (frequency ≤15 min^-1). The resting membrane potential was similar between hyperactive -41.54 ± 3.19 mV (n=11), and active -42.45 ± 1.10 mV (n=27, p>0.05) cells. Hyperactive spikes had a total amplitude of 49.18 ± 4.44 mV and a duration of 7.63 ± 0.92 ms, similar to what was observed in active spikes. In contrast, active cells displayed a frequency of 5.06 ± 0.63 min^-1, significantly different to hyperactive cells (362.05 ± 151.82 min^-1 p<0.05). The amplitude of the after-hyperpolarisation was also significantly different across both groups; 17.80 ± 1.98 mV (hyperactive cells, n=912) and 9.96 ± 1.05 mV (active cells, n=412 p<0.05). Spike potential activity was not affected by the addition of 1µM TTX or 1µM Atropine (n=5 p>0.05), although was abolished upon the addition of 1µM Nifidipine (n=7, p<0.05). Standard transient depolarisations (STDs), (n=32), were recorded in the presence of slow waves (n=10), spikes (n=13) and were also observed in quiescent cells (n=9). STDs displayed similar membrane potentials across the three groups: -53.62 ± 1.31 mV (in the presence of slow waves), -48.46 ± 2.29 mV (spikes) and -51.49 ± 1.70 mV (quiescent cells). STD frequency appeared to be highest when occurring alone (24.55 ± 6.48 min^-1) compared to those in the presence of slow waves or spikes. In contrast, both the duration (49.06 ± 5.36 ms) and amplitude (9.09 ± 0.94 mV) were significantly larger in STDs displayed with spike potentials (p<0.05). The addition of 1µM Nifedipine (n=5) did not significantly affect any of the measured parameters (p>0.05). Conclusions: In summary, the main type of spontaneous electrical activity recorded in the aging guinea pig prostate was spike potentials, which was grouped into hyperactive and active states displaying slightly different properties. Spike potentials were insensitive to 1µM TTX and 1µM Atropine, although were abolished by Nifedipine which suggests the role of L-type calcium channels. Finally, STDs were unaffected by addition of Nifedipine suggesting that mechanisms other than calcium entry via L-type calcium channels are responsible for the generation and maintenance of this activity.