Objectives: To investigate associations between testosterone and patient reported sexual problems and need for sexual care in head and neck cancer patients at time of diagnosis and 6 months after treatment. Patients and methods: Data and samples were used of 40 patients (20 men, 20 women) before and 6 months after treatment. Outcome measures were total testosterone level (TT) and free testosterone index (FTI), testosterone insufficiency (TI), the EORTC QLQ-HN35 Sexuality subscale, the subscales of the International Index of Erectile Function (IIEF), Female Sexual Function Index (FSFI), and the Sexuality subscale of the Short-Form Supportive Care Needs Survey (SCNS-SF34). Results: In men, higher FTI before treatment was significantly associated with better IIEF Orgasm (p = 0.020) and at 6 months follow-up with IIEF Desire (p = 0.019). Before treatment, insufficient testosterone was present in 5 males (25%) and in 3 at follow-up (15%) (2 patients who had TI before treatment plus one). In women, higher TT at follow-up was significantly associated with better EORTC Sexuality (p = 0.031) and FSFI Satisfaction (p = 0.020); FTI at follow-up was associated with FSFI Satisfaction (p = 0.012). Before treatment, TI was present in 2 women (10%) and in 3 (15%) at follow-up (the same 2 patients plus one). Conclusion: This pilot study showed that testosterone seems to be associated with patient reported sexual outcomes among male and female head and neck cancer patients. It is estimated that 10–25% of HNC patients may have testosterone insufficiency before treatment and/or at 6 months after treatment.