In Britain the number of male headed single parent families has increased from 70,000 in 1971 to 90,000 in 1976. Fifty-one lone fathers, who had fulltime care of their five to eleven yearold children after marital separation, were interviewed using a structured schedule. The men's transitions from both the married to separated state and from nuclear to lone fatherhood were examined. The marital rather than the familial transition appeared to be more difficult for the men to negotiate. Mendes' classification of lone fathers into seekers and assenters was investigated. The results indicate that the style in which lone fatherhood came about (conciliatory or aggressive) was a more crucial dynamic than whether or not the father actively chose to become a single parent.