AbstractSome of the marked biochemical and electrophysiological changes provoked by section of the axon in mature neurons suggest that the intracellular calcium concentration ([Ca2+]i) may be increased. We have measured the [Ca2+]iusing the fluorescent indicator Indo‐1 microinjected into rat superior cervical ganglion neurons. No differences in resting [Ca2+]ilevels were found between control neurons and cells which had been axotomized 7–10 days before. However, the rise in [Ca2+]ievoked by orthodromic or antidromic stimulation and the recovery after the stimulating train were considerably slower in axotomized neurons than in control cells. We also found that the number of calbindin‐D28k‐immunopositive cells in the ganglion increases after axotomy, which could be related to the observed differences in calcium home