- Outcome of delivery
- Outlet - see also condition
- Outstanding ears (bilateral) 744.29
- Ovalocytosis (congenital) (hereditary) (see also Elliptocytosis) 282.1
- Ovarian - see also condition
- Ovaritis (cystic) (see also Salpingo-oophoritis) 614.2
- Ovary, ovarian - see condition
- Overactive - see also Hyperfunction
- Overactivity, child 314.01
- Overbite (deep) (excessive) (horizontal) (vertical) 524.29
- Overbreathing (see also Hyperventilation) 786.01
- Overconscientious personality 301.4
- Overdevelopment - see also Hypertrophy
- Overdistention - see Distention
- Overdose overdosage (drug) 977.9
- Overeating 783.6
- Overexertion (effects) (exhaustion) 994.5
- Overexposure (effects) 994.9
- Overfeeding (see also Overeating) 783.6
- Overfill, endodontic 526.62
- Overgrowth, bone NEC 733.99
- Overhanging