diff --git a/.chloggen/mx-psi_requests-remove-methods.yaml b/.chloggen/mx-psi_requests-remove-methods.yaml
new file mode 100644
index 000000000000..ec370d43bf07
--- /dev/null
+++ b/.chloggen/mx-psi_requests-remove-methods.yaml
@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: deprecation
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: exporterhelper
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Deprecate exporterhelper.RequestSizer
+
+# One or more tracking issues or pull requests related to the change
+issues: [13804]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]
diff --git a/exporter/exporterhelper/request.go b/exporter/exporterhelper/request.go
index dcb3046ac387..02187c5d11f3 100644
--- a/exporter/exporterhelper/request.go
+++ b/exporter/exporterhelper/request.go
@@ -32,6 +32,7 @@ type RequestConverterFunc[T any] func(context.Context, T) (Request, error)
 // and accessing it is considered undefined behavior.
 type RequestConsumeFunc = sender.SendFunc[Request]
 
+// Deprecated [v0.136.0]: will be removed in the next minor version.
 // RequestSizer is an interface that returns the size of the given request.
 type RequestSizer = request.Sizer[Request]