Purpose:Fractures of the humerus account for 5％-8％ of all fractures.Nonunion is found with an incidence of up to 15％,depending on the location of the fracture.In case of a manifest nonunion the surgeon faces a challenging problem and has to conceive a therapy based on the underlying pathology.The aim of this study was to describe our treatment concepts for this entity and present our results of the last five years.Methods:Twenty-six patients were treated for nonunion of the humerus between January 2013 and December 2017.Their charts were reviewed retrospectively and demographic data,pathology,surgical treatment and outcome were assessed.Results:The most frequent location for a nonunion was the humeral shaft,with the most common trauma mechanism being multiple falls.Most often atrophic nonunion (n =14),followed by hypertrophic and infection-caused nonunion (each n =4),were found.Our treatment concept could be applied in 19 patients,of which in 90％ of those who were available for follow-up consolidation could be achieved.Conclusion:Humeral nonunion is a heterogeneous entity that has to be analyzed precisely and be treated correspondingly.We therefore present a treatment concept based on the underlying pathology.