diff --git a/CHANGELOG.md b/CHANGELOG.md
index 650a394a..2e3f48ad 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -56,6 +56,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - BoM: Digi-key link in the HTML output.
 - Problems when using more than one dielectric in the stack-up. (#328)
 - Gerber: Extension used for JLCPCB inner layers. (#329)
+- BoM: The length of the CSV separator is now validated.
 
 ## [1.4.0] - 2022-10-12
 ### Added
diff --git a/README.md b/README.md
index 02a7f6a3..c6b40ccc 100644
--- a/README.md
+++ b/README.md
@@ -1435,6 +1435,7 @@ Notes:
           * Valid keys:
             - **`quote_all`**: [boolean=false] Enclose all values using double quotes.
             - **`separator`**: [string=','] CSV Separator. TXT and TSV always use tab as delimiter.
+                               Only one character can be specified.
             - `hide_header`: [boolean=false] Hide the header line (names of the columns).
             - `hide_pcb_info`: [boolean=false] Hide project information.
             - `hide_stats_info`: [boolean=false] Hide statistics information.
diff --git a/docs/samples/generic_plot.kibot.yaml b/docs/samples/generic_plot.kibot.yaml
index aaf23427..d6b30bcd 100644
--- a/docs/samples/generic_plot.kibot.yaml
+++ b/docs/samples/generic_plot.kibot.yaml
@@ -210,7 +210,8 @@ outputs:
         hide_stats_info: false
         # [boolean=false] Enclose all values using double quotes
         quote_all: false
-        # [string=','] CSV Separator. TXT and TSV always use tab as delimiter
+        # [string=','] CSV Separator. TXT and TSV always use tab as delimiter.
+        # Only one character can be specified
         separator: ','
       # [string|list(string)] Include this distributors list. Default is all the available
       distributors:
diff --git a/kibot/out_bom.py b/kibot/out_bom.py
index 2204061a..7a8c78bf 100644
--- a/kibot/out_bom.py
+++ b/kibot/out_bom.py
@@ -247,7 +247,8 @@ class BoMCSV(Optionable):
         super().__init__()
         with document:
             self.separator = ','
-            """ *CSV Separator. TXT and TSV always use tab as delimiter """
+            """ *CSV Separator. TXT and TSV always use tab as delimiter.
+                Only one character can be specified """
             self.hide_header = False
             """ Hide the header line (names of the columns) """
             self.hide_pcb_info = False
@@ -257,6 +258,11 @@ class BoMCSV(Optionable):
             self.quote_all = False
             """ *Enclose all values using double quotes """
 
+    def config(self, parent):
+        super().config(parent)
+        if len(self.separator) != 1:
+            raise KiPlotConfigurationError('The CSV separator must be one character (`{}`)'.format(self.separator))
+
 
 class BoMXLSX(BoMLinkable):
     """ XLSX options """