The distribution of ciliates in a Mexican coastal lagoon was studied. The 4 goals were to: examine small-scale (<100 m) patches; indicate how geostatistical techniques can be used to examine these patches; make inferences concerning ciliate distribution and behaviour in the lagoon using geo- statistical techniques; and assess geostatistics as a method for modelling ciliate distributions. Underly- ing these goals we attempt to make geostatistical techniques accessible to the non-expert. We provide an overview of the methodology, references to the geostatistical literature, and use our system as an example. Ciliates were sampled in a 40 × 40 m grid, divided at 10 m intervals; the grid was further di- vided into subsets, to determine 1 to 10 m scale variation. Between 30 and 35 points were sampled on 2 occasions (January and October). Ciliates were preserved with Lugol's iodine; abundance and spe- cies composition were determined by standard inverted microscopy. The work focused on 4 abundant ciliate species. We indicate, using the variographic analysis, that the abundance of 3 of the 4 ciliates is neither randomly nor homogeneously distributed, but exhibits a structured small-scale patchy distrib- ution. We indicate that species-specific patterns of patchiness exist in stratified and in mixed waters, supporting the notion of behavioural niche-separation of planktonic ciliates. Patches of <13, <18, and <77 m were formed by Lohmaniella oviformis, Tintinnopsis sp. and Strombidium sp., respectively. In contrast, Pleuronema sp. formed patches below the detection limits of the analysis (<1 m). Using geo- statistical techniques, we established variograms and used them to model ciliate distribution and pre- dict ciliate behaviour. Distribution maps were then generated that depicted the shape, distinctness, and gradient of the different patches. After analysing the data, we proposed a working definition of a 'ciliate patch': regions with abundance above the cut-off of the upper quartile from the kriging pre- diction model. Finally, error-maps were developed, indicating the coefficient of variation of the pre- dicted distributions. We conclude that geostatistical analysis is a powerful tool to examine microzoo- plankton at small-scales, and we support its further application in the field.