Negative themes dominate the dream spaces of American, Japanese, Canadian, and Chinese undergraduates. Because negative emotions increase occurrence of negative dream themes, positive themes should dominate the dream space of Nigerians, who have a very high happiness index. Distribution and clustering of themes in dream space were studied among Nigerian undergraduates. Subjects were randomly selected from medical students, who lived in the same hall of residence. Recurrent dream themes in the study questionnaires of American, Canadian, and Chinese undergraduates were revised and categorized as (a) tasks (b) interactions (c) motion, and (d) phenomena. Recurrence of dream themes was graded from 0 to 5. Lifetime prevalence (99% confidence interval) was calculated, and gender differences were compared with the Mantel test. Principal component analysis and feature agglomerative clustering of dream recurrence vectors were performed. Geometric mean age (range) of 196 subjects, 120 men and 76 women, was 24 years (19 -38 years). Total 105 recurrent dream themes were experienced. Geometrical mean (50% interquartile range) of recurrent dreams per person was 33 (24 -55) for all subjects, but 34 (25-57) for men and 31 (24 -50) for women. Positive themes had the highest occurrence and recurrence. Hair dressing and sex themes were significantly different between men and women (p Ͻ .0001). Vectors of recurrent dreams formed concept clusters. Positive themes dominate the dream space of Nigerian undergraduates. Themes are not randomly distributed in dream space. Concepts of awake space are in continuity with dream space.