The results of the 1990 forest condition monitoring programme are presented. A total of 7644 trees were assessed in the main Forestry Commission monitoring programme in 1990. Five species were examined: Sitka spruce (Picea sitchensis), Norway spruce (P. abies), Scots pine (Pinus sylvestris), oak (Quercus spp.) and beech (Fagus sylvatica), distributed over 319 sites. This represents an increase on 1989, and was attributable to an increase in the number of oak plots assessed. Data completeness was high, exceeding 97% in each species. There was a lack of consistency in the way in which individual observers assessed some of the indices. This limited the manner in which the data could be analysed. For example, differences between observers meant that it was not possible to produce reliable maps of specific indices of forest condition. However, assessments of one of the most important of the indices, crown density, were considerably more consistent between surveyors than in previous years.