After reviewing the literature on environmental safety and existing home safety evaluation tools, the researchers developed the Cougar Home Safety Assessment Version 1.0 (Cougar 1.0). This assessment is a 56-item tool for identifying environmental safety hazards in the homes of older persons. The first purpose of this study was to develop and field test the Cougar 1.0 to determine its inter-rater reliability and validity. The second purpose was to identify specific environmental safety hazards in the residences of older persons during the field test. Three graduate occupational therapy students administered the Cougar 1.0 in the homes of 14 older persons within one county of northeastern Pennsylvania. The instrument was found to have a moderate level of inter-rater reliability, as Cohen’s Kappa for the ratings of the 3 raters was .506. Percent agreement between the three raters was 90 percent. The field test found that the most frequently unsafe aspects of the homes were: a lack of grab bars near toilets; no emergency numbers posted near phones; the presence of non-grip throw rugs; lack of fire extinguishers; and lack of step stools. Participating residents and occupational therapy home safety specialists provided positive feedback regarding the content validity of the Cougar 1.0. This research suggests that the use of this instrument by occupational therapists may prevent client injuries in the home.