Aim To identify Heart Failure patients' beliefs towards their medications and how these beliefs relate to adherence. Method Patients attending a multi-disciplinary, community based heart failure clinic on the Gold Coast, Australia were interviewed using a questionnaire composed of fours parts: repertory grid technique; Beliefs About Medicines Questionnaire (BMQ); Medicines Adherence Reporting Scale (MARS); demographic details. Patients were divided into those categorised as adherent (MARS score C 23) and those categorised as non-adherent (MARS score/23). Necessity beliefs scores from BMQ and the frequency of statements generated from the repertory grid portion of the questionnaire were compared between these two groups. Results Forty-three patients were interviewed with a mean age (ᓄ) of 64 (ᱷ) years and thirty-six (83.7 %) were male. Thirty-seven (86.0 %) patients were categorised as adherent; the remaining six (14.0 %) as nonadherent. The 43 patients generated a total of 262 statements about their medicines. The three most common themes identified were Related to fluid (36.6 %), Helps the heart (31.7 %) and Related to weight (13.7 %). There was a significantly higher median necessity score in the adherent group compared to the non adherent group (22.0 vs. 19.5, p = 0.0272). Patients with a strong necessity score also had significantly higher self reported adherence compared to patients with a strong concerns score (21.5 vs. 18.0, p = 0.006). Conclusion This study suggests that patients with heart failure possessing a strong belief in the necessity of their treatment regimen are more likely to demonstrate better adherence.