The authors conducted an internet search and analysed guidelines for testosterone therapy (TTh) produced by the American Urological Association (AUA), European Association of Urology (EAU), American Association of Clinical Endocrinologists (AACE), British Society of Sexual Medicine (BSSM), Endocrine Society (ES), amongst others. TTh in men with testosterone deficiency (TD) is a very controversial topic including diagnostic criteria, screening and treatment. The authors have summarised in well-presented tables the conclusion of guidelines: 1) Various definitions of TD; 2) Population for testosterone testing; 3) Pre-therapy scenarios for adjuvant testing; 4) Key counselling points; 5) Treatment options; 6) Patient monitoring on-therapy. The effects of TTh on prostate cancer and cardiovascular disease were also discussed. There is no correlation between testosterone therapy and prostate cancer from current evidence. However, TTh should be avoided for three to six months in cases of heart failure, recent myocardial infarction and stroke. This paper will make very interesting reading for busy urologists, endocrinologists and general practitioners.