diff --git a/src/llist.c b/src/llist.c
new file mode 100644
index 0000000..a7ac609
--- /dev/null
+++ b/src/llist.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ * Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "llist.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+void llist_init(struct llist *list) {
+	list->first = NULL;
+	list->last = NULL;
+	list->size = 0;
+}
+
+void llist_deinit(struct llist *list) {
+	struct llist_item *aux = list->first;
+	while(aux)
+	{
+		mpz_clear(aux->n);
+		struct llist_item *tmp = aux;
+		aux = aux->next;
+		free(tmp);
+	}
+}
+
+int llist_insert(struct llist *list, mpz_t n) {
+	struct llist_item *aux =
+		malloc(sizeof(struct llist_item));
+	if(!aux)
+	{
+		fprintf(stderr, "ERROR llist_insert(): failed to allocate memory");
+		return 0;
+	}
+	aux->prev = list->last;
+	aux->next = NULL;
+	// TODO: check time complexity of these GMP functions
+	mpz_init(aux->n);
+	mpz_set(aux->n, n);
+
+	if(!list->first)
+		list->first = aux;
+	list->last = aux;
+	list->size++;
+
+	return 1;
+}
diff --git a/src/llist.h b/src/llist.h
new file mode 100644
index 0000000..f5c9cb2
--- /dev/null
+++ b/src/llist.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2019  Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ * Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <gmp.h>
+
+struct llist_item {
+	mpz_t n; // the number stored
+	struct llist_item *next; // the next element in the list
+	struct llist_item *prev; // the previous element in the list
+};
+
+struct llist {
+	struct llist_item *first; // first element of the list
+	struct llist_item *last; // last element of the list
+	size_t size; // number of elements in the list
+};
+
+/*
+ * initialize an empty linked list where `first` and `last` are
+ * equal to NULL and `size` is 0.
+ */
+void llist_init(struct llist *list);
+
+/*
+ * free all space allocated to the list.
+ */
+void llist_deinit(struct llist *list);
+
+/*
+ * insert an item at the end of the linked list with value `n`.
+ *
+ * returns 1 on success, 0 on failure.
+ */
+int llist_insert(struct llist *list, mpz_t n);
+/*
+ * insert an item in the linked list in a sorted position.
+ *
+ * returns 1 on success, 0 on failure.
+ */
+int llist_sorted_insert(struct llist *list, mpz_t n);
diff --git a/src/main.c b/src/main.c
index 25af0a5..baf21f2 100644
--- a/src/main.c
+++ b/src/main.c
@@ -17,6 +17,7 @@
  */
 
 #include "globals.h"
+#include "llist.h"
 
 #include <signal.h>
 #include <stdio.h>