Lipid hydroperoxides are primary oxidation compounds formed in the beginning stages of oxidation and are associated with oxidative stress. Hydroperoxide decomposition also produces low-molecular-weight volatile compounds that are responsible for rancidity in foods. Therefore, the lipid hydroperoxide content is an important determinant in the evaluation of oxidative stress in biological samples and the quality of foods. However, the methods that rapidly determine hydroperoxides in biological samples and foods present various drawbacks such as lack of sensitivity or interferences while methods with greater sensitivity and selectivity require highly trained personnel and/or expensive instrumentation. In this frame, little attention has been devoted to the ferrous oxidation-xylenol orange method, which is based on the peroxide-mediated oxidation of ferrous ions in an acidic medium containing the dye xylenol orange which binds the resulting ferric ions to produce an orange-brown complex. This simple method can be affected by several factors such as the sample matrix, reagents, dye, reaction media, and time, so it has some drawbacks and limitations that need elucidation. These factors have been reviewed to overcome these problems and thus achieve a sensitive, reproducible, and selective method capable of measuring the lipid hydroperoxide content in different matrices.