In Japan, 76.6% of the diabetic population is receiving some kind of treatment. However, concerning patients cared for at home, there have been few reports of needle stick injuries, including injuries during insulin injection. We conducted a fact-finding survey of insulin injection in home-care patients for whom a local pharmacy dispenses insulin. A questionnaire survey was carried out among patients aged 65 years and above for whom insulin was dispensed by 9 pharmacies for self-injection at home and who consented to cooperate in the survey to clarify problems with insulin injection at home. Of the 57 participants, 7 had sustained needle stick injuries caused by themselves. Two incidents of needle stick injuries sustained by a person other than the patient were reported. This survey of 57 patients revealed that there are many problems in self-injection at home and that adverse events are more frequent than recognized by medical staff.