<p>To detect a possible correlation between teratozoospermia and sperm DNA fragmentation (SDF) and to ascertain if teratozoospermia or SDF may predict infertility. We analyzed <i>n</i> = 248,000 spermatozoa for morphology and SDF out of <i>n</i> = 310 consecutive fertile or infertile patients. <i>N</i> = 71/310 patients were found with teratozoospermia (mean normal sperm morphology = 2.2%, SD = 0.7, range = 0.5–3). Teratozoospermia was unable to distinguish fertile from infertile patients. Also, teratozoospermia was detected in all patients with SDF &gt; 20% (i.e., the suggested cut-off for discriminating between fertile and infertile patients). Although the teratozoospermia patients with infertility displayed an increased level of SDF compared to their fertile counterparts, the SDF values were widely overlapping in the two groups. We also analyzed <i>n</i> = 132/310 patients with SDF &gt; 20% and <i>n</i> = 83/ 310 patients with SDF &gt; 30% with or without teratozoospermia. Based on their infertility, the patients were retrospectively classified into two groups. Although the infertile patients displayed increased SDF compared to their fertile counterparts (<i>p</i> &lt; 0.05 for either SDF cut-off), the SDF values were widely overlapping in the two groups. Interestingly, in the group with teratozoospermia or SDF &gt; 30%, cigarette smoking was more represented in the infertile group. 1. SDF analyses are unuseful in teratozoospermia patients; 2. teratozoospermia and SDF cannot differentiate between patients who are fertile or infertile; 3. patients with teratozoospermia or increased SDF should be counseled to stop smoking.</p>