diff --git a/src/dna_seq_indexer.h b/src/dna_seq_indexer.h
index 641652c..750ff5c 100644
--- a/src/dna_seq_indexer.h
+++ b/src/dna_seq_indexer.h
@@ -53,9 +53,33 @@ Obi_blob_p obi_seq_to_blob(const char* seq);
 char* obi_blob_to_seq(Obi_blob_p value_b);
 
 
-// TODO doc
+/**
+ * @brief Stores a DNA sequence in an indexer and returns the index.
+ *
+ * @param indexer The indexer structure.
+ * @param value The DNA sequence to index.
+ *
+ * @returns The index referring to the stored DNA sequence in the indexer.
+ *
+ * @since April 2016
+ * @author Celine Mercier (celine.mercier@metabarcoding.org)
+ */
 index_t obi_index_dna_seq(Obi_indexer_p indexer, const char* value);
 
+
+/**
+ * @brief Retrieves a DNA sequence from an indexer.
+ *
+ * @warning The DNA sequence returned must be freed by the caller.
+ *
+ * @param indexer The indexer structure.
+ * @param idx The index referring to the DNA sequence to retrieve in the indexer.
+ *
+ * @returns A pointer on the DNA sequence.
+ *
+ * @since April 2016
+ * @author Celine Mercier (celine.mercier@metabarcoding.org)
+ */
 char* obi_retrieve_dna_seq(Obi_indexer_p indexer, index_t idx);