Immunofluorescence on cleared intact cochlea allows detailed analysis of the cochlear ultrastructure, while avoiding the problems of dissection and serial sections. Protocols have been developed for mice and Mongolian gerbils. This technical note proposes a detailed and optimised immunofluorescence protocol in the Mongolian gerbil comprising significant quantitative and qualitative improvements. This protocol sequentially comprises: fixation (1 day), decalcification (6 days), pre-treatment (7.5hours), immunolabelling (42hours), dehydration and clearing (23hours), followed by mounting and laser scanning confocal microscopy acquisition. This protocol has been optimised in terms of duration (10 days versus 13 days) with a reduction of the number of steps, improvement of the specificity of immunolabelling and optimisation of the quality of the results obtained. This technical note provides a detailed description of this protocol.