Objective: To estimate the protective effect of storing firearms locked or unloaded, or both, on the risk of suicide by firearms among people with relatively low intention to die.

Design and setting: Cross sectional survey. The 1993 National Mortality Followback Survey of 22 957 deaths in the United States, representing 2.2 million people, conducted by the National Center for Health Statistics.

Participants: Decedent’s next of kin answered questions regarding various aspects of decedent’s life to supplement information from death certificates.

Main results: Compared with decedents who stored their firearm unlocked or loaded, those who stored their firearms locked or unloaded, or both, were less likely to commit suicide by firearms (locked: OR = 0.39, 95% CI = 0.24 to 0.66; unloaded OR = 0.30, 95% CI = 0.18 to 0.49).

Conclusions: This study further supports the utility of devices and practices intended to reduce the likelihood of unauthorised or impulsive use of firearms.