diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0b06303..2d1ecae 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 Changelog
 =========
 
+8.16.1
+------
+
+- Ignore aggregate DMARC reports seen within a period of one hour (#535)
+
 8.16.0
 ------
 
diff --git a/parsedmarc/__init__.py b/parsedmarc/__init__.py
index 8f5923a..38070c4 100644
--- a/parsedmarc/__init__.py
+++ b/parsedmarc/__init__.py
@@ -39,7 +39,7 @@ from parsedmarc.utils import is_outlook_msg, convert_outlook_msg
 from parsedmarc.utils import parse_email
 from parsedmarc.utils import timestamp_to_human, human_timestamp_to_datetime
 
-__version__ = "8.16.0"
+__version__ = "8.16.1"
 
 logger.debug("parsedmarc v{0}".format(__version__))
 
diff --git a/parsedmarc/cli.py b/parsedmarc/cli.py
index 167eba6..c5a7f43 100644
--- a/parsedmarc/cli.py
+++ b/parsedmarc/cli.py
@@ -15,6 +15,7 @@ from ssl import CERT_NONE, create_default_context
 from multiprocessing import Pipe, Process
 import sys
 from tqdm import tqdm
+from expiringdict import ExpiringDict
 
 from parsedmarc import (
     get_dmarc_reports_from_mailbox,
@@ -55,6 +56,8 @@ handler = logging.StreamHandler()
 handler.setFormatter(formatter)
 logger.addHandler(handler)
 
+SEEN_AGGREGATE_REPORT_IDS = ExpiringDict(max_age_seconds=3600)
+
 
 def _str_to_list(s):
     """Converts a comma separated string to a list"""
@@ -1418,7 +1421,12 @@ def _main():
             logger.error("Failed to parse {0} - {1}".format(result[1], result[0]))
         else:
             if result[0]["report_type"] == "aggregate":
-                aggregate_reports.append(result[0]["report"])
+                report_id = result[0]["report"]["report_id"]
+                if report_id not in SEEN_AGGREGATE_REPORT_IDS:
+                    SEEN_AGGREGATE_REPORT_IDS[report_id] = report_id
+                    aggregate_reports.append(result[0]["report"])
+                else:
+                    logger.debug(f"Skipping duplicate report ID: {report_id}")
             elif result[0]["report_type"] == "forensic":
                 forensic_reports.append(result[0]["report"])
             elif result[0]["report_type"] == "smtp_tls":